Arihant Science Class 10 Term 1 Sample Paper

As per CBSE Sample Paper Issued On 02 Sep 2021... Sample Papers Science CBSE Class 10 (Term I) Visit https://telegram.me/booksforcbse for more books.

As per CBSE Sample Paper Issued On 02 Sep 2021... Sample Papers Science CBSE Class 10 (Term I) Authors Kirti Kundu Physics Arshdeep Kaur Chemistry Anam Aarzoo Biology ARIHANT PRAKASHAN (School Division Series)

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Contents þ One Day Revision 1-13 þ The Qualifiers 14-36 þ CBSE Question Bank 37-39 þ Latest CBSE Sample Paper 40-59 Sample Paper 1 63-81 Sample Paper 2 82-101 Sample Paper 3 102-118 Sample Paper 4 119-137 Sample Paper 5 138-154 Sample Paper 6 155-172 Sample Paper 7 173-192 Sample Paper 8 193-210 Sample Paper 9 211-229 Sample Paper 10 230-248 Watch Free Learning Videos Video Solutions of CBSE Sample Papers Chapterwise Important MCQs CBSE Case Based MCQs CBSE Updates Much more valuable content will be available regularly

Syllabus Science CBSE Class 10 (Term I) Units Marks Unit I Chemical Substances-Nature and Behaviour Unit II Chapter : Chemical Reactions and Equations Unit III Chapter : Acids, Bases and Salts Chapter : Metals and Non-metals World of Living Chapter : Life Processes Natural Phenomena Chapter : Light : Reflection and Refraction Chapter : Human Eye and Colourful World THEME MATERIALS THEME THE WORLD OF THE LIVING Unit I Chemical Substances - Nature Unit II World of Living and Behaviour Chapter - Life processes Life Processes : Living Being. Basic concept of Chapter - Chemical Reactions and Equations nutrition, respiration, transport and excretion in plants and animals. Chemical Reactions : Chemical equation, balanced chemical equation, implications of a balanced THEME HOW THINGS WORK chemical equation, types of chemical reactions: combination, decomposition, displacement, double Unit III Natural Phenomena displacement, precipitation, neutralisation, Chapter - Light Reflection and Refraction oxidation and reduction. Reflection of light by curved surfaces; Images formed by spherical mirrors, centre of curvature, Chapter - Acids, Bases and Salts principal axis, principal focus, focal length, mirror formula Derivation not required , magnification. Acids, Bases and Salts : Their definitions in terms of Refraction; Laws of refraction, refractive index. furnishing of H+ and OH ions, general properties, Refraction of light by spherical lens; Image formed examples and uses, concept of pH scale Definition by spherical lenses; Lens formula Derivation not relating to logarithm not required , importance of required ; Magnification. Power of a lens. pH in everyday life; Preparation and uses of sodium hydroxide, bleaching powder, Baking soda, Washing Chapter - Human Eye and Colourful World soda and plaster of Paris. Refraction of light through a prism, dispersion of light, scattering of light, applications in daily life. Chapter - Metals and Non metals Metals and Non-metals : Properties of metals and non-metals; Reactivity series; Formation and properties of ionic compounds.

MCQs Preparation Tips Focus on Theory Learn to Identify Wrong Answers MCQs can be formed from any part or The simplest trick is, observe the options line of the chapter. So, strong command first and take out the least possible one on theory will increase your chances to and repeat the process until you reach solve objective questions correctly and the correct option. quickly. Analyse your Performance Practice of Solving MCQs During the practice of MCQs you can Cracking an MCQ-based examination identify your weak & strong requires you to be familiar with the topics/chapter by analysing of incorrect question format, so continuous practice answers, in this way you will get an will make you more efficient in solving awareness about your weaker topics. MCQs. Practice through Sample Papers Speed & Accuracy Solving more & more papers will make In MCQ-based examination, you need you more efficient and smarter for both speed and accuracy, if your exams. Solve lots of Sample Papers accuracy is good but speed is slow then given in a good Sample Papers book. you might attempt less questions resulting in low score. Attempting MCQs in Exams 1. Read the paper from beginning to Step by step solution is not required in MCQ type questions, it is a waste end & attempt those questions first in of time, you will not get extra marks which you are confident. Now move for this. on to those questions which requires thinking and in last attempt those 4. Most of the time, you need not to questions for which you need more attention. solve the MCQ completely to get the correct option. You can start thinking 2. Read instructions of objective in reverse order and choose the best fit option. questions carefully and find out what is being asked, 5. As there is no negative marking for a bit carelessness can lead you to incorrect answer. incorrect answers, so don't leave any question unanswered. Use your 3. Tick/Write down the correct option guess if you have not exact idea about the correct answer. only while filling the OMR sheet.

CBSE Sample Paper Science Class X (Term I) 1 ONE DAY REVISION Revise All the Concepts in a Day Just Before the Examination... G Chemical Reactions and Equations Chemical Reaction 2. Decomposition Reaction A chemical reaction is a change in which one or more A reaction in which a single reactant breaks down to substance(s) or reactant(s) react(s) to form new form two or more products, is known as decomposition substance(s) with entirely different properties. reaction. e.g. 2Na(s) + 2H2O(l ) 2NaOH(aq) + H2(g) ¯ e.g. CaCO3 ¾He®at CaO(s) + CO2(g) Sodium Water Sodium Hydrogen (Limestone) (Quick lime ) (Carbon dioxide) hydroxide Reactants 3. Exothermic and Endothermic Reactions Products (i) Exothermic Reactions The reactions which are accompanied by the evolution of heat, are called Chemical Equation exothermic reactions (combustion reaction). e.g. respiration. A chemical equation is the symbolic representation of a chemical reaction. Symbols and formulae of the (ii) Endothermic Reactions The reactions which occur reactants and products are used for the same. by the absorption of heat/energy (either in the form of light or electricity), are called endothermic e.g. The reaction of burning of methane gas can be reactions. Photosynthesis and decomposition written as: reactions are example of endothermic reaction. CH4 (g) + 2O2(g) ¾D® CO2(g) + 2H2O(l ) Methane Oxygen Carbon Water 4. Displacement Reaction dioxide Balanced Chemical Equation When a more reactive element displaces less reactive A balanced chemical equation is that in which the total element from its salt solution, it is called displacement number of atoms of each element are equal on both sides of the equation. The balancing of a chemical reaction. e.g. equation is based on law of conservation of mass. Fe(s)+ CuSO4 (aq) ¾® FeSO4 (aq) + Cu(s) Iron Copper sulphate Ferrous sulphate Copper metal (Blue) Or metal ONE DAY REVISION Types of Chemical Reactions Iron (II) sulphate (Green) The chemical reactions are classified into different 5. Double Displacement Reaction classes depending upon the type of chemical changes taking place. These reactions are as follows: The reaction in which two different ions or group of atoms in the reactant molecules are displaced by each 1. Combination Reaction other is called double displacement reaction. It is also A reaction in which two or more reactants combine called precipitation reaction as precipitate is to form a single product, is called combination produced in such reactions. e.g. reaction. Na 2SO4 (aq) + BaCl2(aq) ¾® e.g. CaO(s) + H2O(l ) ¾® Ca(OH)2(aq) + Heat Sodium sulphate Barium BaSO4 ¯ + 2 NaCl(aq) chloride Sodium Barium sulphate Calcium oxide Water Calcium hydroxide chloride (Quick lime) (Slaked lime) (White ppt.)

02 CBSE Sample Paper Science Class X (Term I) 6. Neutralisation Reaction e.g. Reduction The reaction in which acid or acidic oxide react with CuO + H2 ¾H¾eat® Cu + ® ® base or basic oxide to form salt and water are called H2O neutralisation reactions. Copper Hydrogen Copper Water e.g. 2NaOH + H2SO4 ¾® Na 2SO4 + 2H2O oxide (Sodium (Sulphuric (Sodium (Water) Oxidation hydroxide) acid) sulphate) Effects of Oxidation in Everyday Life 7. Oxidation and Reduction Reactions (i) Corrosion The phenomenon due to which metals are slowly eaten away by the reaction of air, water (i) Oxidation It is a process in which a substance and chemicals present in the atmosphere, is called corrosion. loses electrons. Or In which oxygen is added/hydrogen is removed In case of Iron, this process is commonly known as from the substance. rusting of iron. The black coating on silver and the green coating on copper are other examples of e.g. 2Cu + O2 ¾Hea®t 2CuO corrosion. Copper Oxygen Copper oxide (ii) Reduction It is a process in which a substance (ii) Rancidity It is the process of slow oxidation of oil and fat (which are volatile in nature) present in the gains electrons. Or food materials resulting in the change of smell and taste in them. In which hydrogen is added/oxygen is removed from the substance. e.g. 2KClO3 (s) ¾¾D ® 2KCl(s) + 3O2(g) Rancidity can be prevented by keeping food Potassium Oxygen materials in air-tight containers, packing of food Potassium items in packets containing nitrogen gas instead of chloride air, by adding antioxidants, e.g. BHA (Butylated chlorate Hydroxy Anisole) and BHT (Butylated Hydroxy Toluene). (iii) Redox Reactions Those reactions in which oxidation and reduction take place simultaneously, are called redox reactions. G Acids, Bases and Salts Some naturally occurring acids are: Acids Natural source Acid Vinegar Acetic acid Substances which are sour in taste and turns blue litmus to red are called acids. Orange and lemon Citric acid Acids are also defined as those substances Tamarind Tartaric acid which furnish hydrogen ion (H+ ) or hydronium ion (H3O+ ) on dissociation or ionisation in an aqueous Tomato Oxalic acid solution. Curd Lactic acid Chemical Properties of Acids G Acids form salts on reacting with most of the Ant sting and nettle sting Methanoic acid ONE DAY REVISION metals with the evolution of hydrogen gas. Bases or Alkalies e.g. Zn + H2SO4 ¾® ZnSO4 + H2 ­ Substances that furnish hydroxide ions (OH- ) on dissociation or ionisation in an aqueous solution are G Acids reacts with metal carbonates and metal called bases. They are bitter in taste and soapy to touch hydrogen carbonates to produce salt, carbon dioxide and turn red litmus paper into blue. gas and water. Chemical Properties of Bases e.g. CaCO3 + 2 HCl ¾® CaCl2 + H2O + CO2 ­ G Strong bases react with active metals to produce G Acids give salt and water on reaction with metallic hydrogen gas. oxides (basic). e.g. Zn + 2 NaOH ¾® Na 2ZnO2 + H2 ­ e.g. CuO + 2 HCl ¾® CuCl2 + H2O G Oxides of non-metal (acidic) on reaction with base G Strong acids like (HCl, H2SO4 , HNO3, etc.) are give salt and water. completely ionised in water, while weak acids (like H2S, HCN,CH3COOH, etc.) ionises partially in e.g. CO2 + Ca (OH)2 ¾® CaCO3 + H2O water.

CBSE Sample Paper Science Class X (Term I) 03 G Strong bases (like NaOH, KOH, Ca(OH)2, etc.) are (i) Olfactory Indicators Those substances whose completely dissociated or ionised in water, whereas odour changes in acidic or basic medium are called olfactory indicators. e.g. Vanilla extract and weak bases (like NH4OH, Al(OH)3, etc.) ionises only onion. partially. (ii) Universal Indicators To judge how strong a given G Strong bases (like NaOH, KOH, etc.) melt on heating acid or base is, a universal indicator is used which is a mixture of several indicators. It shows different while weak bases (like NH4OH, Mg(OH)2, etc.) colours at different concentrations of hydrogen ion decompose on heating. in a solution. Acids/Bases in Water Solution Strength of Acid and Base In the presence of water, acids give H+ ion. As H+ ion The acids and bases having more ionisation property cannot exist alone, so it combines with water molecules (produced larger number of H+ or OH- ions) are and form H3O+ (hydronium ion). called strong acid and strong base, respectively. In the e.g. HCl + H2O ¾® H3O+ + Cl- same way, the acids and bases which shows less H+ + H2O ¾® H3O+ tendency of ionisation are called weak acid and weak OInHth-eiosna.me way, in presence of water, bases give NaOH(s) ¾H2 O® Na + (aq) + OH-(aq) base, respectively. Both acids and bases produce electric current in their pH Scale aqueous solutions due to the presence of free ions. It is a scale used for measuring hydrogen ion Reaction Between Acids and Bases concentration. It has values ranging from 0 (very acidic) to 14 (very alkaline). Acids react with bases to produce salt and water. This Thus, pH is a number which indicates the acidic or reaction is known as neutralisation reaction. basic nature of a solution. Base + Acid ¾¾® Salt + Water Higher the hydronium ion concentration present in the solution, lower is its pH value [pH means power of Mixing of an acid or base with water is called dilution. hydrogen ions]. Dissolving an acid or base in water is highly exothermic (heat generating) reaction. So, care must be taken G If pH > 7, solution is basic. while doing it. G If pH < 7, solution is acidic. Indicators G If pH = 7, solution is neutral. Indicators are the substances that change their colour 0 Neutral Basic nature increasing 14 or odour when added into an acid or alkaline solution. Acidic nature increasing 7 Indicators can be classified as natural indicators, synthetic indicators, olfactory indicators and universal H+ OH– indicators. Increase in H+ ion Decrease in H+ ion concentration concentration (i) Natural Indicators These indicators are found in Variation of pH with the change in nature in the plants. e.g. Litmus solution is a concentration of H+ (aq) and OH- (aq) ions purple colour dye extracted from the lichen plant. (ii) Synthetic Indicators The indicators which are Importance of pH in Everyday Life synthesised in the laboratory or industry are G Our body works normally within a pH range of known as synthetic indicators. e.g. Methyl orange, phenolphthalein. 7.0 to 7.8. Colour G When pH of rain water goes below 5.6, it is called acid rain. It lowers the pH of the river water and Indicator pH-range (In Acidic (In Basic makes survival of aquatic life difficult. Medium) Medium) G Nature of soil is known by testing its pH and then a ONE DAY REVISION Natural Indicators particular crop is grown in it by selecting suitable fertilizer. Litmus – Red Blue G During indigestion, the stomach produces too much Turmeric – Yellow Red acid, it causes pain and irritation. To correct the disturbed pH range, milk of magnesia (a mild Red cabbage – Red Green base) is used as a medicine, which is also called juice (from leaves) antacid. Synthetic Indicators G If the pH inside the mouth decreases below 5.5 (acidic), the decay of tooth enamel begins. The Phenolphthalein 8.4-10.00 Colourless Pink (Red) bacteria present in the mouth degrades the sugar Methyl orange 3.1-4.4 Red Yellow

04 CBSE Sample Paper Science Class X (Term I) and left over food particles. To prevent tooth decay, (iii) Baking Soda toothpastes (basic) are used which neutralise the excess acid. Chemical Name – Sodium hydrogen carbonate or sodium bicarbonate. G When insects like honeybee, ant, etc., bite, they inject an acid into the skin, that causes pain and irritation. If Common Name – Baking soda a mild base like baking soda is applied on the affected area, it gives relief. Molecular Formula – NaHCO3 Salts It is prepared by using sodium chloride as one of the raw material. NaCl (aq) + H2O (l ) + CO2 (g)+ NH3 (g) Salts are produced by the neutralisation reaction Brine Carbon Ammonia between acid and base. dioxide Acid + Base ¾® Salt + Water ¾® NH4Cl (g)+ NaHCO3(s) Salts of strong acid and a strong base are neutral with (iv) Washing Soda Ammonium Sodium pH value of 7. chloride hydrogen carbonate Salts of a strong acid and weak base are acidic with pH Chemical Name – Sodium carbonate value less than 7. Salts of strong base and weak acid are basic in nature with pH value more than 7. Common Name – Soda ash or crystalline sodium carbonate Common Salt [Sodium Chloride (NaCl)] Molecular Formula – Na 2CO3 ×10H2O Common salt is formed by the combination of Sodium carbonate can be obtained by heating baking hydrochloric acid and sodium hydroxide solution. It is soda. The recrystallisation of sodium carbonate gives obtained on large scale from sea water by separating washing soda. It is also a basic salt. other salts from it. 2 NaHCO3 ¾He®at Na 2CO3 + H2O + CO2 ­ Common salt is an important raw material for various (Sodium hydrogen (Sodium ( Water ) (Carbon materials of daily use, like sodium hydroxide, baking soda, washing soda, bleaching powder, etc. carbonate ) carbonate) dioxide) Na 2CO3 (s) + 10H2O(l ) ¾® Na 2CO3.10H2O( s) (i) Caustic Soda (v) Plaster of Paris ( Washing soda ) Chemical Name – Sodium hydroxide Chemical Name – Calcium sulphate hemihydrate Common Name – Caustic soda Molecular Formula – NaOH Common Name – Plaster of Paris It is prepared by the process called chlor-alkali process. Molecular Formula – CaSO 4 × 1 H2O 2 2NaCl (aq ) + 2H2O (l) Ele¾ct¾ric¾c¾urr®ent 2NaOH(aq ) CaSO4 ×2H2O ¾ 3¾73¾K ® CaSO 4 × 1 H 2O + 3 H 2O 2 2 Sodium chloride Water Sodium hydroxide Gypsum Heat Plaster of Paris + Cl2(g) + H2(g) Plaster of Paris is a white powder and on mixing with Chlorine Hydrogen (At anode) water, it changes to gypsum giving a hard solid mass. (At cathode) (ii) Bleaching Powder This is called setting of plaster of Paris. This reaction is Chemical Name – Calcium hypochlorite or calcium exothermic in nature. oxychloride or chlorite of lime or chlorinated lime. CaSO 4 × 1 H 2O + 3 H2O ¾® CaSO4 ×2H2O 2 2 (Plaster of Paris) (Gypsum) Common Name – Bleaching powder Water of Crystallisation Molecular Formula – Ca(OCl)Cl or CaOCl2 Crystals of some compounds seem to be dry (or anhydrous) but actually contain, some water ONE DAY REVISION It is produced by the action of chlorine on dry slaked molecules attached to them. These water molecules are called water of crystallisation and such salts are lime. called hydrated salts. Ca(OH)2 + Cl2 ¾¾D ® CaOCl2 + H2O Slaked Chlorine Bleaching lime powder

CBSE Sample Paper Science Class X (Term I) 05 G Metals and Non-Metals On the basis of properties, elements can be divided into Exception Some metal oxides such as aluminium two main groups, i.e. metals and non-metals. Apart oxide, zinc oxide show both acidic and basic from these, some elements show properties of both behaviour. These are called amphoteric oxides. metals and non-metals. These are called metalloids. 2. Reaction of Metals with Water Metals Metals react with water and produce a metal oxide and Those elements which form positive ions by losing hydrogen gas. Metal oxides that are soluble in water electrons are called metals. e.g. copper, iron, aluminium, dissolves in it further to form metal hydroxide. sodium etc. Metal + Water ¾® Metal oxide + Hydrogen gas Physical Properties of Metals Metal oxide + Water ¾® Metal hydroxide The various physical properties of metals are as follows e.g. 2K(s) + 2H2O(l ) ¾® 2KOH(aq) + H2(g) (i) Hardness Most of the metals are hard. Some alkali Potassium (Cold) Potassium Hydrogen metals like lithium, sodium and potassium are so hydroxide soft that they can be easily cut with a knife. + Heat (ii) Ductility It is the property due to which a metal can Ca(s) + 2H2O(l ) ¾® Ca(OH)2(aq) + H2(g) be drawn into thin wires. Gold is the most ductile metal. Calcium Water Calcium Hydrogen hydroxide (iii) Malleability It is the property of metal due to which it (cold) (less violent) can be beaten into thin sheets. Gold and silver are the most malleable metals. 3. Reaction of Metals with Acids (iv) Electrical conductivity The conduction of (i) Reaction of metals with dil. HCl Except a few less electricity or flow of electric current occurs due to reactive metals (such as Cu, Hg, Ag, Au, Pt etc), all the flow of free electrons present in the metal. metals react with dilute sulphuric acid and hydrochloric acid to produce salt and hydrogen (v) Good conductor of heat Generally metals are gas. good conductors of heat, except lead and mercury, which are poor conductors of heat. Metals like Metal + Dilute acid ¾¾® Salt + Hydrogen copper and silver are the best conductors of heat. (ii) Reaction of metals with dil. HNO3 Hydrogen gas (vi) Melting and boiling points Metals generally have is not evolved when a metal reacts with nitric acid. high melting and boiling points. Tungsten has the This is due to strong oxidising nature of nitric acid. It highest melting point among metals, while gallium oxidises the H2 produced to water and itself get and caesium have very low melting points. reduced to any of the nitrogen oxide (N2O, NO, NO2 ). These two metals will melt if we keep them on our But magnesium (Mg) and manganese (Mn) react palm. with very dil. HNO3 to evolve H2 gas. Metal + HNO3 ¾® Salt + NO2 / N2O ­ + H2O (vii) Sonority The metals that produce a sound on striking a hard surface are said to be sonorous. (Dil.) Note All metals (except mercury) exist as solid at room Exceptional case (Only for Mn and Mg) temperature. Metal (Mn/Mg) + HNO3 ¾® Salt + H2 ­ Chemical Properties of Metals (Dil.) Most of the chemical properties of metals are due to their electropositive nature. It means metal atom loses Note Aqua-regia (Latin for ‘royal water’) ONE DAY REVISION electrons to form cations. It is a freshly prepared mixture of concentrated M ¾® Mn+ + ne - hydrochloric acid and concentrated nitric acid in (Metal atom) the ratio of 3 : 1. 1. Reaction of Metals with Oxygen 4. Reaction of Metals with Solutions of Other Metal Salts (Burning in Air or Formation of Oxides) Reactive metals can displace a comparatively less Almost all metals combine with oxygen (or air) to form reactive metal from its compounds in aqueous salt metal oxides, which are basic in nature. solution or in molten form. Metal A + Salt solution of B ¾® Salt solution of A + Metal + Oxygen ¾® Metal oxide Metal B This type of reaction is called displacement reaction.

06 CBSE Sample Paper Science Class X (Term I) The Reactivity Series of Metals Chemical Properties of Non-metals On the basis of their relative tendency to lose electron Non-metals do not react with water, steam or dilute and their reactive nature, metals are arranged in a series, acids to evolve hydrogen gas. this series is called activity series or reactivity series of metals. But on heating, readily form oxides or salts with conc. acids. Reactivity Series (activity series) of Metals S(s) + 2H2SO4 (conc. ) H¾e®at 3SO2(g) + 2H2O(l ) S(s) + 6HNO3(conc. ) ¾H¾ea¾t ® H2SO4 (aq) K Potassium (Most reactive metal) + 6 NO2(g) +2H2O(aq) Na Sodium (Reddish These Ca Calcium brown vapour) metals are more Mg Magnesium reactive Non-metals also show displacement reaction like metals. than Al Aluminium e.g. Cl2 (g) + 2NaBr (l ) ¾® 2NaCl (l )+ Br2 (g) hydrogen Decreasing chemical reactivity Zn Zinc Chlorine Sodium Sodium Bromine bromide chloride Fe Iron Sn Tin Reaction between Metals and Non-Metals (Ionic Bond Formation) Pb Lead H Hydrogen Metals have a tendency to loose electrons to form cations (+ve ions) and non-metals have a tendency to These Cu Copper gain electrons to form anions (-ve ions). metals Hg Mercury are less Ag Silver When metals and non-metals react with each other reactive Au Gold then both of them tries to achieve completely filled than outermost shell by the transfer of electrons. hydrogen ( Least reactive metal ) This type of chemical bond formed by the complete Non-metals transfer of electrons from one atom to another is called ionic bond. Such compounds are called ionic Those elements which form negative ions by gaining compounds. electrons are called non-metals, e.g. iodine, sulphur, oxygen, hydrogen etc. The non-metals are either solids For example or gases except bromine which is a liquid. Na ¾¾® Na + + e- Physical Properties of Non-metals (2,8,1) (2,8) (Sodium cation) The various physical properties of metals are as follows : Cl + e- ¾¾® Cl- (i) Malleability and ductility Non-metals are neither (2,8,7) (2,8,8) malleable nor ductile, i.e. they cannot be beaten into (Chloride anion) thin sheets or drawn into wires. Na·+´ ´´ ´´ ¾® [Na+] [ Cl´· ´ ´ ´´- ] ´´ Cl ´´ ONE DAY REVISION (ii) Brittleness Non-metals are brittle in nature. Properties of Ionic Compounds For instance, sulphur is a brittle solid. If it is hammered, it breaks into pieces. (i) Physical nature Ionic compounds are hard crystalline solids because of strong forces (iii) Physical state Most of the non-metals are soft of attraction between the positive and negative (if solid). Only diamond, an allotropic form of carbon ions. is the hardest known substance. (ii) Melting and boiling points These compounds (iv) Lustre Non-metals do not have lustre, i.e. shining have high melting and boiling points surface. However, diamond, graphite (the allotropic forms of carbon) and iodine have lustre. (iii) Solubility These compounds are soluble in water (polar solvent) and insoluble in organic solvents (v) Electrical and thermal conductivity Non-metals are (non-polar solvent) like kerosene, benzene, ether, generally poor conductors of heat and electricity. petrol etc. Graphite, an allotrope of carbon, is a good conductor of electricity. (iv) Conduction of electricity Ionic or electrovalent compounds are good conductors of electricity, but (vi) Melting and boiling points Generally, non-metals they conduct electricity either in molten form or in their have low melting and boiling points. But non-metals aqueous solution. that are solids have comparatively higher boiling points, e.g. B, Si, C etc.

CBSE Sample Paper Science Class X (Term I) 07 G Life Processes I. Nutrition Examples are fungi like yeast, bread moulds and mushroom. Some organisms take food from other All life processes require energy to carry out their organisms without killing them. These are called functions. This energy is obtained from carbon-based parasites, i.e. Cuscuta, orchids, ticks, lice, leeches food sources through the process called nutrition. and tapeworms. There are two modes of nutrition, i.e. autotrophic and G In Amoeba, digestion occurs in the food vacuole, heterotrophic. formed by the engulfing of food by its pseudopodia. The undigested food is moved to the surface of the Autotrophic Mode of Nutrition cell and thrown out. G Autotrophic nutrition is performed by the autotrophs Nutrition in Human Beings that synthesis organic food in the form of carbohydrates from carbon dioxide and water in the G In mouth, food is crushed into small particles presence of sunlight and chlorophyll to convert them through chewing and mixed with saliva, which into stored forms of energy. This process of food contains amylase for digestion of starch. synthesis is known as photosynthesis. Examples of autotrophs are green plants (producers) and some G Food is swallowed and passes through the pharynx bacteria. and oesophagus to reach stomach. The gastric juice contains pepsin (for digesting proteins), HCl and G General reaction involved in process of mucus. photosynthesis is ¾S¾un¾lig¾h¾t ® G Hydrochloric acid mainly provide an acidic environment for the protein digestion by pepsin. The 6CO2 + 12H2O Chlorophyll C6H12O 6 mucus protects the lining of the stomach from the action of the acid under normal conditions. Carbon dioxide Water Carbohydrate G Liver secretes bile which emulsifies fat. Pancreatic + 6O2 + 6H2O juice contains enzymes amylase, trypsin and lipase for digesting starch, proteins and fats, Oxygen Water respectively. G Major events occurring in photosynthesis are G In the small intestine, carbohydrate, proteins and fats are completely digested into glucose, amino acids (i) Absorption of light energy by chlorophyll. fatty acids, gylcerol and respectively. The villi of small intestine absorb the digested food and supply it to (ii) Conversion of light energy into chemical energy every cell of the body. (iii) Splitting of water molecules into hydrogen and G Herbivores have longer small intestine for cellulose oxygen. digestion. (iv) Reduction of carbon dioxide to carbohydrates. G The undigested food is egested out from the body through the anus. The exit of this waste material is G Leaf in green plants have some structures known as regulated by the anal sphincter. chloroplasts (containing chlorophyll) which are the main site for the process of photosynthesis to Mouth/Buccal cavity Oesophagus (food pipe) occur. Salivary glands G Stomata are the tiny pores present on the surface of Tongue leaves, through which gaseous exchange occurs for photosynthesis. The opening and closing of the pore is a function of guard cells. Guard cells Stomata pore Liver Stomach Chloroplast Diaphragm Pancreas (a) (b) Gall bladder Large intestine ONE DAY REVISION Open stomatal pore Close stomatal pore (stores bile) (colon) Heterotrophic Mode of Nutriton Bile duct Rectum Appendix G Heterotrophs are organisms which are dependent on other organisms for their food. The heterotrophs may Small intestine be herbivores, carnivores, parasites or saprophytes. Human digestive system G Some organisms breakdown the food into basic molecules outside their body then absorb them.

08 CBSE Sample Paper Science Class X (Term I) II. Respiration G The alveoli provides a surface where the exchange of gases can take place. The walls of the alveoli contains Respiration is the breaking down of nutrients to an extensive network of blood-vessels. When we release energy. During respiration, the digested breathe in, we lift our ribs and flatten our diaphragm and food materials are broken down to release energy in the chest cavity becomes larger as a result. Because of the form of ATP. this, air is sucked into the lungs and fills the expanded alveoli. Depending on the requirement of oxygen, respiration occurs by following two ways: G The blood brings carbon dioxide from the rest of the body for release into the alveoli, and the oxygen in (i) Aerobic respiration It occurs in presence of the alveolar air is taken up by blood in the alveolar oxygen. blood vessels to be transported to all the cells in the body. (ii) Anaerobic respiration It occurs in absence of oxygen. In both kinds of respiration, the first step is Nasal passage breakdown of glucose into pyruvate. This process takes place in cytoplasm. Mouth cavity Pharynx Absence of Larynx Trachea oxygen Alveoli Rings of cartilage (in yeast) Ethanol (2-carbon molecule) + Carbon dioxide In + Energy cytoplasm Pyruvate Lack of oxygen Glucose (3-carbon Lactic acid (6-carbon (in our (3-carbon molecules) Lung molecule muscle cells) + Energy Ribs molecule) + Presence of Energy) oxygen Bronchi Carbon dioxide Respiratory (in + Water + Energy bronchioles Bronchioles mitochondria) Alveolar sac Diaphragm Breakdown of glucose by various pathways Human respiratory system ONE DAY REVISION Respiration in Plants Respiratory Pigment G Plants respire through stomata, lenticels (present Haemoglobin (which has very high affinity for oxygen) is on stem) and through the process of diffusion in the respiratory pigment in human beings. It is mainly roots. responsible to carry oxygen from lungs to tissues, before releasing it. It is also responsible for the red colour of Red G In leaves, respiration takes place by diffusion of Blood Corpuscles (RBCs). oxygen through stomata into the cells of the leaf from where carbon dioxide is released into the III. Transportation atmosphere. Transportation is a life process in which a substance Respiration in Animals absorbed (or made) in one part of the body of an organism is carried to other parts of the body through the G The aquatic organisms (such as fishes etc) circulating fluids like blood and lymph. utilise the oxygen dissolved in water for respiration. Aquatic organisms breathe more Transportation in Human Beings rapidly (through mouth) to accumulate more and more oxygen because the amount of dissolved The transport system of human beings consists of a oxygen is fairly lower in water than the amount of circulating fluid called blood, which is pumped by a oxygen in the air. muscular organ known as heart and a system of interconnecting tubes, i.e. blood vessels. G In terrestrial organisms, atmospheric oxygen is used for respiration and this oxygen is absorbed Heart by different organs in different animals. G The heart acts like a pumping machine in our body that G In human beings, air is taken into the body pushes out the blood into the blood vessels. through the nostrils. G Human heart is four chambered, (i.e., two upper atria G From here, the air passes through the throat, into (singular : atrium) and two lower ventricles). the lungs. Rings of cartilage are present in the throat, which ensures that the air passage does G Oxygen-rich blood from lungs comes to thin walled upper not collapse. chamber of the heart, left atrium which then contracts and transfer blood to left ventricle. G Within the lungs, the passage divides into smaller and smaller tubes which finally terminates in G The left ventricle contracts and blood is pumped to the balloon-like structures, called alveoli. body parts.

CBSE Sample Paper Science Class X (Term I) 09 G Deoxygenated blood enters in right atrium and when it Blood Pressure contract, it transfers blood to right ventricle, it pumps blood to the lungs for oxygenation. G The force that blood exerts against the wall of a vessel is called blood pressure. G Ventricles have thick walls than atrium because they have to pump blood into various organs. G The normal systolic pressure is about 120 mm of Hg and diastolic pressure is 80 mm of Hg. Aorta G It is measured with an instrument called Vena cava Pulmonary arteries sphygmomanometer. from upper Pulmonary veins body Maintenance by Platelets Left atrium Right atrium Blood has platelet cells which circulate around the body and plug the site of injury by forming a blood Vena cava clot. from lower Lymph body G Apart from blood, lymph in our body is an another type of fluid involved in transportation. This is also Right called tissue fluid. ventricle Left ventricle G Lymph drains into lymphatic capillaries from the intercellular spaces, which join to form large lymph Septum vessels that finally open into larger veins. (dividing wall) G It is also meant to carry any digested and Sectional view of the human heart absorbed fat from intestine and drains excess fluid from extracellular space back into the blood. G There are three types of vessels involved in blood circulation; arteries, veins and capillaries Transportation in Plants (i) Arteries The arteries have thick, muscular and elastic G On the contrary, plants take simple compounds as walls which carry blood at high pressure. They do not carbon dioxide and water and stored them as food have valves. It carries blood away from the heart to in leaves. Roots absorb raw materials, water and various organs of the body. minerals from soil. (ii) Veins The veins have thin walls than arteries which G Xylem and phloem carry substances from one carry blood at low pressure. They have valves part of the plant body to the another. to prevent the back flow of blood. It collects the blood from different organs and bring it back to the G Xylem transports water and minerals obtained from heart. the soil, whereas phloem (vascular tissue) transports products of photosynthesis from the (iii) Capillaries Capillaries are formed when artery divides leaves to the other parts of the plant. into smaller tubes. The walls of capillaries are one cell thick. Exchange of materials between blood and Transport of Water surrounding thick cells takes place across the thin walls of capillaries. G There is a concentration gradient between roots and soil, so, water moves into roots from soil and G Humans show double circulation and complete creates a water column pushed upwards. Alone separation of oxygenated and deoxygenated blood. In pressure is not enough. double circulation, the blood passes through the heart twice during each cycle. G Transport of water occurs also due to transpirational pull. Lung capillaries Transpiration Pulmonary Pulmonary vein G Transpiration is the loss of water in the form of ONE DAY REVISION artery to lungs from lungs vapour from the aerial parts (i.e., stem, leaves) of the plant. It takes place through the special pores Vena cava Aorta to body known as stomata. from body G Transpiration helps in the absorption and upward Capillaries in body movement of water and minerals dissolved in it organs apart from the lungs from roots to the leaves. Schematic representation of transport G In day time, transpiration pull is the major driving and exchange of gases source in the movement of water in the xylem. Transport of Food and Other Substances G Translocation is the phenomenon of transport or movement or soluble products (sugar) from the leaves to the other parts of the plant by the help of phloem.

10 CBSE Sample Paper Science Class X (Term I) G Sugar like sucrose is transferred into phloem G The collecting duct finally gathers all the materials that has tissue by the help of energy (ATP). not returned to the blood through the tubular membranes. G It occurs in sieve tubes with the help of adjacent companion cells. Bowman’s capsule Glomerulus Tubular part of nephron Branch of Excretion renal artery G Excretion is the biological process by which Renal artery Collecting duct an organism removes the metabolic wastes Branch of from the body. renal vein G Unicellular organisms excrete waste by simple Capillaries process like diffusion, whereas multicellular organisms use specialised organs for the removal of waste products. Excretion in Human Beings Structure of a nephron G In humans, a pair of kidneys, a pair of ureters, G The urine formed in each kidney, then enters a long tube, urinary bladder and urethra constitutes the the ureter (which connects the kidneys with the urinary excretory system. bladder). Left renal artery G Urine is stored in the urinary bladder for sometime before eliminating through urethra (an opening by which urine Left renal vein passes out). Aorta Left kidney G Pressure of the expanded bladder leads to the urge to pass Inferior vena it out through the urethra. Right cava ureter Haemodialysis Urinary Urethra bladder G In case of kidney failure, an artificial kidney is used. It is a device to remove nitrogen waste products from the blood Human excretory system through the dialysis. G Each kidney has thousand of tiny tubules G It is different from natural kidney as the process of called nephron i.e., filteration unit which are reabsorption does not occur in artificial kidney. closely packed together). Excretion in Plants G The urine is formed to filter out waste products from the blood. G Plants give off gaseous wastes like carbon dioxide and oxygen through stomata and lenticels during respiration G The blood then passes through the tubular and photosynthesis. part of nephron (where important or useful substances such as glucose, amino acids, G Plants also get rid of excess of water by the process of fats and a major amount of water are transpiration and can also store waste substances in old selectively reabsorbed by the tubular part) of xylem such as resins and gums. the nephron. G Some plants store waste substances in the cell vacuoles and get rid of them by dropping their leaves. e.g., deciduous plants. While, other some plants also excrete some solid waste substances into the soil around them. G Light : Reflection and Refraction Reflection of Light Laws of Reflection The phenomenon of bouncing back of light rays There are two laws of reflection: on striking an opaque surface, is called reflection of light. (i) The incident ray, reflected ray and normal at the point of incidence, all lie in the same plane. Normal ONE DAY REVISION (ii) Angle of incidence is always equal to angle of Reflected ray reflection, i.e. Ði = Ðr. Incideranyt Spherical Mirror ir It is the mirror which has spherical reflecting surface. They are Angle of incidence Angle of reflection of two types: Reflection from plane surface (i) Convex mirror/diverging mirror The spherical mirror with outward curved reflecting surface.

CBSE Sample Paper Science Class X (Term I) 11 (ii) Concave mirror/converging mirror The spherical Refraction of Light mirror with inward curved reflecting surface. The phenomenon of bending of light from its original Image Formation by Concave Mirror path on entering another medium of different density. Nature and Incident ray Incident ray Size of Position of Position of Image i i Object Image Rarer Denser At infinity At focus or in Real, inverted, Denser r the focal plane extremely r Rarer diminished in size Refracted ray Refracted ray Beyond the Laws of Refraction centre of curvature but at Between focus Real, inverted and (i) The incident ray, the normal and the refracted ray, finite distance and the centre diminished all lie in the same plane. from mirror of curvature (ii) Ratio of sine of angle of incidence to the sine of At the centre of At the centre Real, inverted and angle of refraction for light of single wavelength is same constant for a given pair of media (Snell’s law) curvature of curvature size as that of i.e. sin i = m, constant (m or h) object sin r This constant is known as refractive index (m). Between focus Beyond the Real, inverted and Refractive Index and centre of centre of magnified curvature curvature 1m 2 represents refractive index of medium 2 with respect to medium 1, when light is going from medium Real, inverted and 1 to medium 2. = m2 = sin i extremely 1m 2 m1 sin r At the focus At infinity magnified Between the Behind the Virtual, erect where, m 2 is called the absolute refractive index of and medium 2. magnified pole and focus mirror Refraction through a Rectangular Glass Slab Image Formation by Convex Mirror When a light ray enters into a glass slab, then the emergent ray is parallel to the incident ray but it is Nature and shifted sideward slightly. Size of Position of Position of Image Incident ray N1 Object Image i At the principal Virtual, erect A Air B focus, behind and extremely (rarer) the mirror diminished At infinity Glass Refracted rayr Between the Virtual, erect slab r Between infinity principal focus and diminished (denser) and the pole and the pole, (i.e. at finite behind the D C distance) mirror e Air Emergent ray (rarer) Mirror Formula N2 It is expressed as 1 + 1 = 1 Lens Lateral ONE DAY REVISION vuf displacement where, u = object distance from pole of mirror Refraction through glass slab v = image distance from pole of mirror and f = focal length of mirror It is a transparent medium bounded by two surfaces, atleast one of which is curved. Magnification Lenses are of two types: m = Height of image (hi ) = -v (i) Convex or converging lens A lens which is thicker Height of Object (h0 ) u at the centre and thinner at its end is called convex lens.

12 CBSE Sample Paper Science Class X (Term I) (ii) Concave or diverging lens A lens which is Image Formation by a Concave Lens thinner at the centre and thicker at its ends is called concave lens. Position of Position of Nature and Size Object Image of Image Image Formation by a Convex Lens At infinity At focus on same Virtual, erect side of lens as and highly Position of Position of Nature and Size Anywhere object diminished Object Image of Image between optical centre Between focus Virtual, erect At infinity At F2 Real, and infinity and optical and diminished inverted and centre, on the extremely same side of lens diminished as object Beyond 2F1 Between F2 and Real, inverted Lens formula (at finite 2 F2 and diminished It is expressed as, 1 - 1 = 1 distance) Real, inverted vu f At 2F1 At 2F2 and of same size as that of object Magnification Between F1 Beyond 2F2 m = hi = v and 2 F1 Real, inverted and Power of a Lens ho u At F1 At infinity magnified The ability of a lens to converge or diverge light rays is Between On same side of Real, inverted called power (P) of the lens. It is defined as the lens and F1 the lens as the and highly reciprocal of focal length, object magnified i.e. P [in Dioptre (D)] = 1 = 100 Virtual, erect and f(in cm) f(in cm) magnified For combination of lenses, P = P1 + P2 + P3 + … G Human Eye and the Colourful World Refraction of Light through a Prism A Prism is a transparent refracting medium bounded by White light R (Red) Spectrum of white light two plane surfaces, inclined to each other at a certain angle. It has one triangular base and three rectangular BC O (Orange) lateral surfaces. Y (Yellow) Dispersion of white light by a prism G (Green) Angle of prism (A) A H Adnegvlieatoiofn (d) B (Blue) M I (Indigo) N G V (Violet) D i r r ee REmergent ray E F S Incident ray Q Recombination of White Light N¢ M¢ P Newton obtained white light using similar prism in inverted position. BC ONE DAY REVISION Refraction of light through a triangular glass prism A P2 Screen Dispersion of White Light by a Glass Prism White light R Recombination R R White light G The phenomenon of splitting of white light by prism into its constituent colours is called dispersion of VV white light. Slit Dispersion V G The group of different colours of light rays P1 A produced by the prism due to dispersion is called First prism Second prism spectrum. Recombination of spectrum of white light

CBSE Sample Paper Science Class X (Term I) 13 Rainbow Scattering of Light It is a natural spectrum appearing in the sky after a rain The reflection of light from an object in all directions is shower. It is caused by dispersion of sunlight by tiny water called scattering of light. The colour of scattered light droplets, present in the atmosphere. depends upon the size of scattering particles and wavelength of light. Atmospheric Refraction Some phenomena based on scattering of light are: The refraction of light caused by the Earth’s atmosphere, which consists of air layers of varying (i) Tyndall effect The scattering of light when it optical densities, is called atmospheric refraction. passes through a colloidal solution is called Tyndall Some phenomena based on atmospheric refraction effect. The Earth’s atmosphere is a heterogenous are: mixture of minute particles of smoke, tiny water droplets, suspended particles of dust and (i) Twinkling of stars The twinkling of a star is due to molecules of air, which becomes visible due to atmospheric refraction of star's light. The scattering of light. continuously changing atmosphere refracts the light by different amounts. In this way, the intensity (ii) Colour of the sky During the day time sky appears of star light reaching our eyes increases and blue. This is because the size of the particles in the decreases continuously and the star appears to atmosphere are comparable to the wavelength of twinkle at night. blue light, so they scatter the light of shorter wavelengths (blue end of spectrum) and hence, the (ii) Advance sunrise and delayed sunset This is sky appears blue. because of atmospheric refraction. When the Sun is slightly below the horizon, the Sun’s light coming (iii) Colour of sun at sunrise and sunset At sunrise from less dense to more dense air, is refracted and sunset, the sun appears red. . Near the horizon downwards. most of the blue light and shorter wavelength is scattered away by the particles of the size Because of this, the Sun appears to be raised comparable to these wavelengths. Therefore, the above the horizon and so the rising Sun can be light that reaches our eyes is of longer wavelength. seen about 2 min before actual sunrise. Similarly, This gives rise to the reddish appearance of Sun. the Sun can be seen for about 2 min even after the Sun has set below the horizon. ONE DAY REVISION

14 CBSE Sample Paper Science Class X (Term I) THE QUALIFIERS Chapterwise Set of MCQs to Check Preparation Level of Each Chapter 1. Chemical Reactions and Equations Direction (Q. Nos. 1-15) Each of the question has four options out of which only one is correct. Select the correct option as your answer. 1. The equation given below depicts which type of chemical reaction? A + BC ¾® AC + B (a) Combustion (b) Combination (c) Decomposition (d) Displacement 2. Identify the substance that is oxidised and the substance that is reduced in the following reaction CuO(s) + H 2(g) ¾® Cu(s) + H 2O(l) Oxidised Reduced H2 (a) CuO CuO (b) H2 Cu (c) H2O H2O (d) Cu 3. Salman took some copper turnings and added them to silver nitrate solution. What would he observe? (a) The solution turned blue (b) Yellow precipitate was formed (c) White precipitate was formed (d) The solution turned red 4. Identify gas A evolved at anode in the given setup. Plastic mug THE QUALIFIERS Test tube (a) Oxygen Graphite Water (d) Carbon dioxide rod Rubber stopper Anode Cathode Switch 6V Battery (b) Ozone (c) Hydrogen

CBSE Sample Paper Science Class X (Term I) 15 5. A white salt X Brown fumes Residue Which of the following two combinations are correct? 1. X - Reduction reaction 2. X - Endothermic reaction 3. X - Decomposition reaction 4. X - Displacement reaction (a) 1 and 2 (b) 2 and 3 (c) 3 and 4 (d) 1 and 4 6. Which of the following correctly represents a balanced chemical equation? (a) 2HNO3 + Ca(OH)2 ¾® Ca(NO3 )2 + 2 H2O (b) NaOH + H2SO4 ¾® Na2SO4 + 2H2O (c) NaCl + AgNO3 ¾® 2 AgCl+NaNO3 (d) BaCl2 + H2SO4 ¾® BaSO4 + HCl 7. An element X on exposure to moist air turns reddish brown and a new compound Y is formed. The substance X and Y are XY (a) Fe Fe2O3 (b) Cu CuO (c) Ag (d) Al Ag2S Al2O3 8. Which of the following condition is necessary for a chemical reaction? (a) It must be accompanied with change in temperature and pressure (b) It must follow the law of conservation of mass (c) It must be accompanied with change in state (d) It must be accompanied with production of energy 9. Shivani performed a reaction in which the addition and removal of oxygen taken place simultaneously. Choose the correct name for the reaction? (a) Oxidation reaction (b) Reduction reaction (c) Redox reaction (d) Precipitation reaction 10. Limestone Slaked lime P Quick lime Q THE QUALIFIERS Identify the correct option from the given table which represents the type of reaction occurring in step P and Q respectively. Endothermic Exothermic (a) P P (b) O P (c) P O (d) O O

16 CBSE Sample Paper Science Class X (Term I) 11. A substance added to food containing fats and oils to prevent rancidity is called. (a) Oxidant (b) Rust (c) Coolant (d) Antioxidant 12. The table shows below gives information about four different types of processes. S.No. Name of process Word equation 1. Combustion Hydrogen + Oxygen ¾® Water 2. Photosynthesis Carbon dioxide + Water ¾S¾un¾lig¾ht® Glucose + Oxygen + Water Chlorophyll 3. Combination Limestone ¾H¾e¾at® Quick lime + Carbon dioxide 4. Photodecomposition Silver bromide ¾L¾ig¾ht® Silver + Bromine Identify the process that is correctly paired with its word equation. (a) 1 and 2 (b) 2 and 3 (c) 2 and 4 (d) 1 and 3 13. Which of the following statements about the given reaction are correct? 3Fe(s) + 4H2O(g) ¾® Fe 3O4 (s) + 4H2 (g) (i) Iron metal is getting oxidised. (ii) Water is getting reduced. (iii) Water is acting as reducing agent. (iv) Water is acting as oxidising agent. (a) (i), (ii) and (iii) (b) (iii) and (iv) (c) (i), (ii) and (iv) (d) (ii) and (iv) 14. Which of the following are exothermic processes? (i) Reaction of water with quick lime (ii) Dilution of an acid (iii) Evaporation of water (iv) Sublimation of camphor (crystals) (a) (i) and (ii) (b) (ii) and (iii) (c) (i) and (iv) (d) (iii) and (iv) 15. Na 2SO 4 + BaCl2 ¾® BaSO 4 + 2NaCl Identify the correct option from the given table which represents the type of reactions occuring in the given reaction. Double displacement reaction Precipitation reaction Oxidation (a) P PP (b) P PO (c) P OP (d) O PP THE QUALIFIERS Answers 1. (d) 2. (b) 3. (a) 4. (a) 5. (b) For Detailed Solutions 6. (a) 7. (a) 8. (b) 9. (c) 10. (a) Scan the code 11. (d) 12. (c) 13. (c) 14. (a) 15. (b)

CBSE Sample Paper Science Class X (Term I) 17 2. Acids, Bases and Salts 1. A girl met with an accident and her leg get fractured. She went to an orthopedics for treatment. The doctor mixed a white powder in water and applied it to her leg. What could be the white powder is? (a) Talcum powder (b) Paris of plaster (c) Plaster of Paris (d) Copper phosphate 2. Identify the colour of wet blue litmus paper brought near the mouth of delivery tube in the following experiment. Wet limus paper Delivery tube Cork Test tube Conc. H2SO4 NaCl (a) The litmus paper will turn red (b) The litmus paper will remain blue (c) The litmus paper will turn green (d) The litmus paper will dry 3. Aman added a few mL of conc. sulphuric acid to zinc granules. Which of the following reaction takes place when metal zinc reacts with it? (a) Zn + 2H2SO4 ¾® ZnSO3 + 2 H2O + 2SO2 (b) Zn + 2H2SO4 ¾® Na2ZnO2 + H2 (c) Zn + 2H2SO4 ¾® ZnSO4 + SO2 + 2H2O (d) Zn + H2SO4 ¾® ZnSO4 + H2 4. Consider the following reaction, Iron (II) B chloride Sodium A Hydrogen C Ammonium chloride Chloride D chloride Lead THE QUALIFIERS chloride Here, A, B, C and D respectively are (a) A = Conc. HCl; B = Fe; C = NH4 OH; D = PbO (b) A = Conc. H2SO4 ; B = Fe; C = NH4OH; D = Pb(NO3 )2 (c) A = Conc. H2SO4 ; B = Fe; C = NH3 ; D = Pb(NO3 )2 (d) A = Conc. HCl; B = Fe; C = NH3 ; D = PbO

18 CBSE Sample Paper Science Class X (Term I) 5. On a pH scale, pH of blood is shown below. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 What is the nature of blood? (b) Highly alkaline (a) Neutral (d) Slightly acidic (c) Slightly alkaline 6. 14 12 10 pH 8 6 4 2 0 ABCD The graph given below depicts the pH value of four different chemicals A, B, C and D. Which of the following is least acidic? (a) A (b) B (c) C (d) D 7. Seema added a few drops of ethanoic acid to solid sodium carbonate. What would she observed? (a) A separate layer of acid is formed (b) A hissing sound was produced (c) A black precipitate was formed (d) Brisk effervescence of CO2 was observed 8. Which of the following compounds should be added to the beaker, so that the bulb will glow? 6 volt battery Bulb Switch Beaker I. Nail Solution of X Rubber cork THE QUALIFIERS 1. Dilute HCl (b) 1 and 4 2. Alcohol (d) 2 and 4 3. Glucose 4. Lime water Codes (c) 2 and 3 (a) 1 and 2 9. The table shown below gives information about four substances A, B, C and D. Substance pH value A 8.7 B 5.5 C 1.7 D 12.3

CBSE Sample Paper Science Class X (Term I) 19 Identify the basic compounds from the above given substances. (a) A and B (b) B and C (c) A and D (d) C and D 10. A student adds a few drops of the universal indicator to a solution of dilute sodium hydroxide acid in the way shown here. He would observe that the colour of the solution changes from colourless to Drops of universal indicator Dilute sodium hydroxide solution (a) red (b) yellow (c) violet (d) green 11. On adding a few drops of universal indicator to three unknown colourless solutions P, Q and R taken separately in three test-tubes shown in the following diagrams. A student observed the changes in colour as green in P, red in Q and violet in R. (P) (Q) (R) Green Red Violet Write the correct decreasing order of pH of the solutions. (a) P > Q > R (b) Q > P > R (c) R > Q > P (d) R > P > Q 12. Which of the following is an incorrect match? (a) Bleaching powder—CaOCl2 (b) Caustic soda—NaOH (c) Baking soda—NaHCO3 (d) Washing soda—Na2CO3 × 4H2O 13. Which of the following statements is correct regarding neutralisation reaction? 1. Salts are produced by the process of neutralisation between acid and base. THE QUALIFIERS 2. Oxygen and water are liberated as byproducts. 3. Salts of strong acid and strong base are neutral in nature. 4. Common salt is formed by the process of neutralisation. Codes (b) 1, 3, 4 (c) 2, 3, 4 (d) 1, 2, 3 (a) 1, 2, 4

20 CBSE Sample Paper Science Class X (Term I) 14. At cathode At anode H2 CI2 NaOH De-greasing metals, soaps Fuels, margarine Water treatment, swimming pools, and detergents, paper ammonia for fertilizers PVC, disinfectants, CFCs. pesticides making, artificial fibres Which of the following two products are obtained from the process shown in the given figure? 1. HCl 2. Bleach 3. Litmus 4. H 2SO 4 Codes (a) 1 and 2 (b) 1 and 3 (c) 1 and 4 (d) 2 and 4 15. Identify the compound X on the basis of the reactions given below. Also, choose the correct chemical formulae of A, B and C. ¾+¾Zn ® A Compound X ¾+¾HCI® B + H2O ¾+C¾H3C¾OO®H C + H2O XA BC (a) NaOH Na2ZnO2 NaCl CH3COONa (b) NaCl Na2ZnO2 NaOH CH3COONa (c) HCl Na2ZnO2 H2SO4 CH3COONa (d) CH3COONa NaOH NaCl Na2ZnO2 Answers 1. (c) 2. (a) 3. (d) 4. (c) 5. (c) For Detailed Solutions 6. (d) 7. (d) 8. (b) 9. (c) 10. (c) Scan the code 11. (d) 12. (d) 13. (b) 14. (a) 15. (c) THE QUALIFIERS 3. Metals and Non-metals 1. Ajay took calcium oxide in an iron container. He slowly added some water to it. What would he observe? (a) The container becomes cold (b) The container becomes hot (c) Green coloured solution is formed (d) White precipitate is formed

CBSE Sample Paper Science Class X (Term I) 21 2. Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it, as shown in figure below. Gas A Test tube Spatula containing sulphur powder Burner Collection of gas Identify gas A in the given experiment. (a) SO2 (b) SO (c) HS (d) S 8 (d) CuSO4 + Fe 3. Which of the following can undergo a chemical reaction? (a) MgSO4 + Fe (b) ZnSO4 + Fe (c) MgSO4 + Pb 4. Metal React with Yes P cold water No React with Yes Q steam No R Which of the following two combinations are correct? 1. P—Sodium, Q—Aluminium 2. P—Aluminium, Q—Zinc 3. Q—Zinc, R—Lead 4. Q—Copper, R—Silver (a) 1 and 3 (b) 2 and 4 (c) 3 and 4 (d) 1 and 4 5. The graph given below depicts number of electrons in an atom of different elements A, B, C and D. Numbers of electrons 10 8 6 4 2 0 ABCD Which of the following element is a metal? (a) A (b) B (c) C (d) D 6. Aluminium sulphate and copper sulphate solutions were taken in two test tubes I and II, THE QUALIFIERS respectively. A few pieces of iron filings were then added to both the solutions. The four students A, B, C and D recorded their observations in the form of a table as given. Student Aluminium sulphate solution (I) Copper sulphate solution (II) A Colourless solution changes to light green. Blue colour of the solution is retained. B Colourless solution does not change. Blue colour of the solution changes to green. C Colourless solution changes to light blue. Blue colour of the solution changes to green. D Colourless solution remains unchanged. Blue colour of the solution fades away.

22 CBSE Sample Paper Science Class X (Term I) Which of the above represents the correct set of observations that would be recorded by the student? (a) A (b) B (c) C (d) D 7. The composition of aqua-regia is (b) Conc. HCl : Dil. HNO3 3:1 (a) Dil.HCl : Conc. HNO3 3:1 (d) Dil. HCl : Dil. HNO3 3:1 (c) Conc. HCl : Conc. HNO3 3:1 8. A more reactive metal displaces a less reactive metal from the aqueous solution of the latter. From the following sets tell which one represents a correct picture of both the possible () and impossible () reactions between metals and the solutions of different salts? Metal Al2 (SO4 )3 CuSO4 FeSO4 ZnSO4 (a) Al     (b) Cu     (c) Fe     (d) Zn     9. A student performed the following four experiments, CuSO4 (aq) CuSO4 (aq) CuSO4 (aq) CuSO4 (aq) Al Zn Fe Cu I II III IV In which experiment(s) would he find the formation of a solid deposition? Codes (b) I and II (a) I, II and IV (d) II, III and IV (c) I, II and III 10. A student takes four test tubes containing solutions of different colours marked I, II, III and IV as shown below. The table given below gives information about four solution I, II, III and IV. THE QUALIFIERS Solutions Colour of solutions I Colourless Blue II Orange Pale green III IV Which test tubes could be containing copper sulphate solution and ferrous sulphate solution? Codes (a) I and II, respectively (b) II and IV, respectively (c) I and III, respectively (d) III and IV, respectively

CBSE Sample Paper Science Class X (Term I) 23 11. An electrician want to use a piece of element to complete a broken electric circuit. He has elements W, X, Y and Z as follows Elements Properties W Insulator Melting point Ductility X P Low O O High P Y P Low P Z O High O Which of the above element is useful for the electrician? (a) W and Z (b) X only (c) Y only (d) Z and X 12. Elements XY Z Mercury Boron Carbon Identify the correct option from the given table which represent the type of elements according to their respective examples. XY Z (a) Metal Non-metal Metalloids (b) Non-metal Metal Metalloids (c) Metal Metalloids Non-metal (d) Non-metal Metalloids Non-metal 13. Which of the following element form amphoteric oxides? (a) Cu (b) Al (c) K (d) Fe 14. Which of the following statement is correct? (d) 1 and 3 (d) A and C 1. Aqua regia is a highly corrosive, fuming liquid. 2. Non-metals are non-malleable but are ductile. 3. NaCl is an ionic compound. 4. Metalloids show properties of both metals and non-metals. Codes (b) 1, 3, 4 (c) 2, 3, 4 (a) 1, 2, 4 15. The electronic configuration of A, B and C are A : 2, 8 B : 2, 8, 7 C : 2, 8, 1 THE QUALIFIERS Which of the given element is a non-metal? (a) A (b) B (c) C Answers 1. (b) 2. (a) 3. (d) 4. (a) 5. (a) For Detailed Solutions 6. (b) 7. (c) 8. (a) 9. (c) 10. (b) Scan the code 11. (b) 12. (a) 13. (b) 14. (b) 15. (b)

24 CBSE Sample Paper Science Class X (Term I) 4. Life Processes Direction (Q. Nos. 1-30) Each of the question has four options out of which only one is correct. Select the correct option as your answer. 1. Carefully study the diagram of the cross-section of leaf with lables (i) to (iv). Select the correct option which gives correct identification and main function and/or characteristics. Waxy cuticle (i) (ii) Air spaces (iii) (iv) Stomatal pore (a) (i)-Upper epidermis – It contains large number of stomata. (b) (ii)-Chloroplast – Site for photosynthesis (c) (iii)-Guard cell – Protective layer of cells (d) (iv)-Lower epidermis – It has no stomata 2. Identify the option that indicates the correct information about labels (i) and (ii). (i) (ii) (a) (i)—Systematic circulation, (ii)—Pulmonary circulation (b) (i)—Systematic circulation, (ii)—Systematic circulation (c) (i)—Pulmonary circulation, (ii)—Systematic circulation (d) (i)—Double circulation, (ii)—Single circulation 3. Which of the following option perform same functions? (a) Stomata and veins (b) Stomata and lenticels (c) Lenticels and xylem (d) Sieve tube and stomata THE QUALIFIERS 4. Which of the following is an example of excretion? (a) Release of insulin from the pancreas (b) Release of saliva from the salivary glands (c) Removal of carbon dioxide from the lungs (d) Removal of faces from the alimentary canal 5. In which order do these events occur in human nutrition? (a) Digestion ® Ingestion ® Absorption ® Assimilation (b) Digestion ® Ingestion ® Assimilation ® Absorption (c) Ingestion ® Digestion ® Absorption ® Assimilation (d) Ingestion ® Digestion ® Assimilation ® Absorption

CBSE Sample Paper Science Class X (Term I) 25 6. The blood returning to the heart from lungs via pulmonary veins has more (a) RBC per mL of blood (b) haemoglobin per mL of blood (c) oxygen per mL of blood (d) nutrients per mL of blood 7. Observe the diagram of human respiratory system. A Nasal Pharynx passage Larynx Trachea Bronchi (windpipe) B D Respiratory bronchioles Bronchioles C Match the labelling referred in Column I and correlate it with the Column II. Column I Column II A 1. They helps in the expansion and contraction of thoracic cavity. B 2. They are the structural and functional unit of lungs. C 3. It is part through which air is taken in. D 4. It always contain a residual volume. Codes B CD A B CD A 4 21 (b) 3 1 4 2 2 14 (d) 3 4 1 2 (a) 3 (c) 3 8. Identify the option that indicates the correct order of organ involve in urine formation, storage and passing out of urine. Left renal artery Left renal vein Aorta (i) THE QUALIFIERS Inferior vena (ii) cava (iii) (a) (i) Kidney, (ii) Ureter, (iii) Urethra (b) (i) Kidney, (ii) Urinary bladder, (iii) Urethra (c) (i) Kidney, (ii) Urethra, (iii) Ureter (d) (i) Kidney, (ii) Urinary bladder, (iii) Ureter

26 CBSE Sample Paper Science Class X (Term I) 9. Taking their number into account, select the correct pair. (a) Ureter and urinary bladder (b) Kidney and urinary bladder (c) Urethra and urinary bladder (d) Urethra and kidney 10. Find out the incorrect statement given below. (a) Length of small intestine in various animals depend upon the type of food they eat (b) Enzymes for digestion of carbohydrates are not secreted in gastric juice (c) In an organism, different enzymes have different pH (d) Absorption of nutrients mostly occur in large intestine 11. Identify the option that indicates the correct blood vessels connected at location (i), (ii), (iii) and (iv). (i) (ii) (iii) (iv) (a) (i) Vena cava , (ii) Aorta, (iii) Pulmonary artery, (iv) Pulmonary vein (b) (i) Vena cava, (ii) Pulmonary vein, (iii) Pulmonary artery, (iv) Aorta (c) (i) Vena cava, (ii) Pulmonary artery, (iii) Pulmonary vein, (iv) Aorta (d) (i) Vena cava, (ii) Aorta, (iii) Pulmonary vein, (iv) Pulmonary artery 12. The liquid which collects in the cavity of Bowman’s capsule is (a) concentrated urine (b) blood plasma minus proteins (c) glycogen and water (d) used bile for excretion 13. The deoxygenated blood from the body first enters (a) into right atrium through vena cava (b) into left atrium through vena cava (c) into right ventricle through vena cava (d) into left ventricle through vena cava THE QUALIFIERS 14. In a person, the Bowman’s capsule of the nephron is not functioning at all. What will its effect be on urine formation? (a) The urine will not be formed (b) The blood will not be filtered properly (c) Quantity and quality of urine will be unaffected (d) No effect will be seen 15. What happens to the inhaled air as it passes through the nasal cavity? (a) Warmed to the body temperature (b) Moistened by mucus (c) Filtered in the nasal cavity (d) All of the above

CBSE Sample Paper Science Class X (Term I) 27 16. Observe the diagram of nephron given below. A Glomerulus B C From another nephron D Structure of a nephron Match the labelling referred in Column I and correlate with the function in Column II. Column I Column II A 1. It carries the filtered blood away from the kidney. B 2. It is involve in filtration of blood. C 3. It collects the urine. D 4. Involved in the selectively reabsorption of the substances. Codes B CD A B CD A 4 13 (b) 4 2 1 3 4 31 (d) 2 3 4 1 (a) 2 (c) 2 17. The figure given below shows a human respiratory system with labels (i) to (iv). Identify the correct label with its function and/or characteristics. (i) (ii) (iii) THE QUALIFIERS (iv) (a) (i) Nasal passage ® Have presence of half rings to ensure that passage does not collapse (b) (ii) Pharynx ® It is a common passage for air and food (c) (iii) Bronchi ® These are smaller tubes that leads to the alveoli (d) (iv) Diaphragm ® It is the site for gaseous exchange 18. Trypsin differs from pepsin in digestion of protein in (a) acidic medium (b) alkaline medium (c) neutral medium (d) different pH range

28 CBSE Sample Paper Science Class X (Term I) 19. What will happen, if mucus is not secreted by the gastric glands? (a) Action of enzyme pepsin will be reduced (b) Acidic medium will not be created (c) It will lead to the corrosion of stomach wall due to HCl (d) The breakdown of protein will not occur 20. In case of kidney failure, an artificial kidney can be used. Which one of the following is not correct for it? (a) It is used to remove nitrogenous waste products from the blood (b) It is different from normal kidney because there is no reabsorption involved (c) The dialysing fluid has the same osmotic pressure blood (d) The dialysing fluid contain some amount of nitrogenous waste 21. Identify the option that indicates the correct substrate for enzyme that is secreted in location (i), (ii) and (iii). (i) (ii) (iii) (b) i—Proteins, ii—Proteins, iii—Lipids (d) i—Starch, ii—Lipids, iii—Proteins (a) i—Starch, ii—Proteins, iii—Lipids (c) i—Starch, ii—Lipids, iii—Starch 22. Excretion primarily involves (a) removal of excess heater (b) removal of all byproducts during catabolism (c) removal of byproducts during anabolism (d) removal of nitrogenous wastes THE QUALIFIERS 23. The secretion released into the small intestine are (a) bile and pancreatic juices (b) pancreatic juices, bile and intestinal juices (c) pancreatic juices and intestinal juices (d) intestinal juices only 24. Which of the following is not the function of hydrochloric acid? (a) Creating acidic medium in stomach (b) Digestion of proteins (c) Facilitate the function of pepsin (d) Killing of microbes present

CBSE Sample Paper Science Class X (Term I) 29 25. The figure shown below shows a schematic plan of blood circulation in humans with labels (i) to (iv). Identify the correct label with its functions. (i) (ii) (iv) (iii) (a) (i) Capillaries of body organs ® Exchange of gases and substances take place and deoxygenated blood is then carried to lungs (b) (ii) Pulmonary artery ® Carry oxygenated blood to the lungs (c) (iii) Capillaries of lungs ® Exchange of gases takes place and oxygenated blood is carried back to heart via pulmonary vein (d) (iv) Pulmonary vein ® carry oxygenated blood to the body parts 26. The rate of breathing is much faster in aquatic organisms than those of terrestrial organisms because (a) the availability of oxygen is fairly high in water (b) the gills are better developed respiratory organs than lungs (c) the availability of oxygen is fairly low in water (d) they take in water through mouth 27. The wall of the ventricle are much thicker than of atrium because (a) it has to pump the blood to distant location (b) it always receive oxygenated blood (c) it is present below the atrium (d) it has to store the blood 28. The figure given below shows human digestive system with labels (i) to (iv). Identify the correct labels with its function and/or characteristics. (i) (iii) THE QUALIFIERS (ii) (iv)

30 CBSE Sample Paper Science Class X (Term I) (a) (i) Liver—It stores bile (b) (ii) Small intestine—Maximum absorption of water occurs (c) (iii) Stomach—Digestion of proteins begins here (d) (iv) Large intestine—Absorption of digested food takes place 29. Identify the phase of digestion which is represented in the diagram of nutrition in Amoeba. Arrow indicates the flow of stages of nutrition process. Nucleus (a) Pseudopodia Food particle Food vacuole (b) Food particle (c) Undigested food (d) removed Nutrition in Amoeba (a) The pseudopodia forms the food vacuole for the egestion of undigested food (b) The pseudopodia fuses over the food particle forming a food vacuole for the absorption of the food (c) The pseudopodia forms the food vacuole for the excretion (d) The pseudopodia fuses over the nucleus forming a food vacuole for the absorption of food 30. Which of the following will not occur, if the guard cells stop working ? (a) Regulation of transpiration (b) Conduction of food (c) Conduction of water (d) Decolouration of leaves Answers 1. (b) 2. (c) 3. (b) 4. (c) 5. (c) For Detailed Solutions 6. (c) 7. (d) 8. (b) 9. (c) 10. (d) Scan the code 11. (b) 12. (b) 13. (a) 14. (b) 15. (d) 16. (a) 17. (b) 18. (b) 19. (c) 20. (d) 21. (a) 22. (d) 23. (b) 24. (b) 25. (c) 26. (c) 27. (a) 28. (c) 29. (b) 30. (c) THE QUALIFIERS 5. Light : Reflection and Refraction 1. The velocity of light in glass is 2 ´ 108 m/s and that in air is 3 ´ 108 m/s. By how much would an ink dot appear to be raised, when covered by a glass plate 6.0 cm thick? (a) 2.0 cm (b) 4.0 cm (c) 6.0 cm (d) 1.5 cm 2. A point object is placed at the centre of a glass sphere of radius 6 cm and refractive index 1.5. The distance of the virtual image from the surface of the sphere is (a) 2 cm (b) 4 cm (c) 6 cm (d) 12 cm

CBSE Sample Paper Science Class X (Term I) 31 3. n1 n2 q1 q2 Which of the following is not the correct representation of Snell’s law? (a) n1 sinq 1 = n2 sinq 2 (b) n1 = sinq 2 n2 sinq 1 sinq 1 (c) n2 = sinq 2 (d) n1 sinq 2 = n2 sinq 1 n1 4. If a symmetrical convex lens of focal length f is cut as shown f f¢ New focal length of lens is f ¢, which of the following is correct? (a) f > f ¢ (b) f = 1 (c) f = f ¢ (d) f ¢ = 2 f f¢ 5. Which of the following factors determine the focal length of a lens? (a) Radii of curvature of the surface of the lens (b) Nature of material of the lens (c) Nature of medium in which lens is placed (d) All of the above 6. An object is held at a distance of 60 cm from a convex mirror of focal length 20 cm. At what distance from the convex mirror, should a plane mirror be held so that image in the two mirrors coincide? (a) 37.5 cm O FC THE QUALIFIERS (c) 15 cm 60 cm (b) 22.5 cm 7. n2 (d) 75 cm n1 A concave lens made of a material of refractive index n1 is kept in a medium of refractive index n2 . A parallel beam of light is incident on the lens as shown. Complete the path of rays of light emerging from the concave lens if n1 < n2 .

32 CBSE Sample Paper Science Class X (Term I) n1 n1 n1 n1 n2 n2 n2 n2 (a) (b) (c) (d) 8. Study the given ray diagrams and select the correct statement from the following. XX Screen Screen 20 cm 25 cm (a) Device X is a concave mirror and device Y is a convex lens, whose focal lengths are 20 cm and 25 cm respectively. (b) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 10 cm and 12.5 cm respectively. (c) Device X is a concave lens and device Y is a convex mirror, whose focal lengths are 20 cm and 25 cm respectively. (d) Device X is a convex lens and device Y is a concave mirror, whose focal lengths are 20 cm and 25 cm respectively. 9. A student, while doing the experiment on tracing the path of a ray of light passing through a rectangular glass slab, measured the three angles marked as q 1, q 2 and q 3 as shown. q1 q2 THE QUALIFIERS q3 His measurements could be correct if he were to find (a) q 1 < q 2 < q 3 (b) q 1 < q 2 but q 1 = q 3 (c) q 1 > q 2 > q 3 (d) q 1 > q 2 but q 2 = q 3 10. For same angle of incidence, lateral displacement of a ray on passing through a glass slab is (a) inversely proportional to thickness of glass slab (b) directly proportional to thickness of glass slab (c) not depend upon thickness of glass slab (d) directly proportional to square of thickness of glass slab.

CBSE Sample Paper Science Class X (Term I) 33 11. A tank of water when viewed normally appears to be 1 m deep. Calculate its actual depth if refractive index of water is 4. 3 (a) 4 m (b) 3 m 3 4 (c) 5 m (d) 3 m 3 5 12. A convex lens of power 3 D is held in contact with a concave lens of power -1 D. A parallel beam of light is made to fall on the combination. At what distance from the combination will the beam get focused? (a) 2 cm (b) 25 cm (c) 0.5 cm (d) 50 cm 13. The refractive index of diamond is 2.47 and that of glass is 1.51. How much faster does light travel in glass than in diamond? (a) 1.51 times (b) 1.635 times (c) 2.47 times (d) 1.845 times 14. A child runs towards a plane mirror with a velocity of 2 m/s. With what speed will her image move towards her? (a) 2 m/s (b) zero (c) 4 m/s (d) 6 m/s 15. Which statement best describes the property of light waves illustrated in the diagram below? (a) Some materials absorb light waves. (b) Some materials are refracted by some materials. (c) Light waves are refracted by some materials. (d) Light waves are emitted by some materials. Answers 1. (a) 2. (c) 3. (d) 4. (c) 5. (d) For Detailed Solutions THE QUALIFIERS 6. (b) 7. (b) 8. (d) 9. (b) 10. (b) Scan the code 11. (a) 12. (d) 13. (b) 14. (c) 15. (c)

34 CBSE Sample Paper Science Class X (Term I) 6. The Human Eye and the Colourful World 1. A beam of white light is incident from glass to air on glass-air interface such that green light just suffers TIR. The colours of the light which will come out to air are (a) Yellow, orange, red (b) Violet, indigo, blue (c) All colours (d) All colours except green 2. A prism ABC (with BC as base) is placed in different orientations. A narrow beam of white light is incident on the prism as shown in figure. AC B CC AA B CA (iii) B B (i) (ii) (iv) In which of the following diagrams, after dispersion, the first colour from the top of the spectrum corresponds to the colour of the Blood? (a) (i) (b) (ii) (c) (iii) (d) (iv) 3. Which of the following is the correct plot between the angle of deviation (d) and angle of incidence (i) for a triangular prism? dd dd (a) i (b) i (c) i (d) i 4. When the prism in dispersion experiment is rotated slowly, then it is observed that I. white light comes out of the prism on a nearby screen. II. a band of seven colours is observed on a nearby screen with red and indigo colours at the two ends. III. a band of seven colours is observed on a nearby screen with yellow and violet colours at the two ends. IV. a band of seven colours is observed on a nearby screen with red and violet colours at the two ends. Select the incorrect observations (a) I and II (b) II and III (c) I, II and III (d) I, III and IV 5. Which of the following is correct? THE QUALIFIERS (a) l blue > l yellow > lgreen (b) l yellow > lgreen > l blue (c) l yellow > l blue > lgreen (d) lgreen > l blue > l yellow 6. At noon the sun appears white as (a) light is least scattered (b) all the colours of the white light are scattered away (c) blue colour is scattered the most (d) red colour is scattered the most

CBSE Sample Paper Science Class X (Term I) 35 7. The image shows a light ray incident on a glass prism B C AD FE The various angles are labelled in the image. Which angle shows the angle of incidence and angle of refraction respectively? (a) D and A (b) F and C (c) B and D (d) A and D 8. Why do stars appear to twinkle at night? (a) Because the light of stars travels in different media (b) Because the distance of star varies when earth rotates (c) Because the star changes its position, relative to earth (d) Because the atmosphere reflects the light at different angles. 9. Match Column I with Column II. Column I Column II A Blue sky p. Group of colours B Rainbow q. Changing atmosphere C Spectrum r. Scattering D Delayed sunset s. Suspended water droplets A B CD A B CD (a) r p s q (b) q r p s (c) r s p q (d) s p q r 10. A ray of light is inclined to one face of a prism at an angle of 50° as shown. 42° 50° If the angle of prism is 60°, find the angle which the emergent ray makes with the second face of the prism. (a) 28° (b) 52° (c) 48° (d) 62° 11. THE QUALIFIERS X White light Y Z Examine the above diagram and choose the correct one. (a) X is violet, Y is white light and Z is red (b) Y is red, X is violet and Z is white light (c) Y is violet, X is red and Z is yellow light (d) X is red, Y is violet and Z is white light

36 CBSE Sample Paper Science Class X (Term I) 12. A student wants to know about scattering of light, so he noted down his observations I. The path of light becomes visible due to scattering of light. II. Tyndall effect occurs in colloidal solution III. Earth’s atmosphere is a homogeneous mixture of minute particles. IV. Size of colloidal particles is relatively larger than true solution molecules. Which one of the following is incorrect about Tyndall effect? (a) I and III (b) III (c) II and IV (d) I and IV 13. What is the difference in time of actual sunrise and advanced sunrise? (a) 4 minutes (b) 3 minutes 56 seconds (c) 2 minutes (d) 1 minute 14. Select the incorrect statements about rainbow I. Rainbow is caused by scattering of sunlight by tiny water droplets, present in the atmosphere. II. A rainbow is always formed in a direction opposite to that of the sun. III. The water droplets refract and scatter the incident sunlight, then reflect it internally, and finally refract it again when it comes out of the raindrop. IV. Different colours reach the observer’s eye due to the scattering of light and internal reflection. (a) Both (I) and (II) (b) Both (II) and (III) (c) (I), (III) and (IV) (d) (II), (III) and (IV) 15. The velocity of waves of all colours is same in (a) water (b) oxygen (c) vacuum (d) glass Answers 1. (a) 2. (a) 3. (c) 4. (c) 5. (b) For Detailed Solutions 6. (a) 7. (d) 8. (a) 9. (c) 10. (a) Scan the code 11. (b) 12. (b) 13. (c) 14. (c) 15. (c) THE QUALIFIERS

CBSE Sample Paper Science Class X (Term I) 37 CBSE QUESTION BANK Case Study Based Questions 1. Read the following and answer any (iii) Gas A, obtained above is a reactant for a very important biochemical process four questions from (i) to (v). which occurs in the presence of sunlight. Identify the name of the process. Marble's popularity began in ancient Rome and Greece, where white and off-white (a) Respiration (b) Photosynthesis marble were used to construct a variety of structures, from hand-held sculptures to (c) Transpiration (d) Photolysis massive pillars and buildings. (iv) Marble statues are corroded or stained when they repeatedly come into contact with polluted rain water. Identify the main reason. (i) The substance not likely to contain CaCO 3 is (b) a marble statue (a) dolomite (c) calcined gypsum (d) sea shells (ii) A student added 10 g of calcium (a) Decomposition of calcium carbonate to carbonate in a rigid container, secured it calcium oxide tightly and started to heat it. After some time, an increase in pressure was (b) Polluted water is basic in nature, hence observed, the pressure reading was then it reacts with calcium carbonate noted at intervals of 5 min and plotted against time, in a graph as shown below. (c) Polluted water is acidic in nature, hence During which time interval did maximum it reacts with calcium carbonate decomposition took place? (d) Calcium carbonate dissolves in water to 1.25 give calcium hydroxide. CBSE QUESTION BANK 1.00 (v) Calcium oxide can be reduced to calcium, by heating with sodium metal. Pressure (atm) 0.75 Which compound would act as an oxidising agent in the above process? 0.50 (a) Sodium (b) Sodium oxide 0.25 (c) Calcium (d) Calcium oxide (a) 15-20 min (b) 10-15 min (c) 5-10 min (d) 0-5 min Sol. (i) (c) The substance not likely to contain CaCO3 is calcined gypsum. The composition of gypsum is CaSO4 × 2H2O. It does not have CaCO3. Marble is composed of recrystallised carbonate minerals, most commonly calcite (CaCO3) or dolomite (CaMg(CO3 )2 ) Hence, option (c) is correct.

38 CBSE Sample Paper Science Class X (Term I) (ii) (d) The pressure reading was noted at intervals of (b) MnO2 is getting oxidised whereas HCl is 5 min and plotted against time of the reaction which getting reduced. involved: CaCO3 ¾D® CaO + CO2 ­ (c) MnO2 and HCl both are getting reduced. (d) MnO2 and HCl both are getting oxidised. formation of CO2 gas increases pressure and is maximum in (0-5) min graph as shown sharp curve in (iv) In the above discussed reaction, what is the (0-5) min. nature of MnO2? (a) Acidic oxide Hence, option (d) is correct. (b) Basic oxide (iii) (b) Gas A (CO2), for a very important biochemical (c) Neutral oxide process which occurs in the presence of sunlight, the (d) Amphoteric oxide name of the process is photosynthesis. The reactants for photosynthesis are light energy, (v) What will happen, if we take dry HCl gas water, carbon dioxide and chlorophyll, while the instead of aqueous solution of HCl? products are glucose, oxygen and water. (a) Reaction will occur faster (b) Reaction will not occur (iv) (c) Marble statues are corroded or stained when they (c) Reaction rate will be slow repeatedly come into contact with polluted rain water. (d) Reaction rate will remain the same Polluted rain water is acidic in nature. Hence, it reacts with calcium carbonate. Sol. CaCO3(s) + H2SO4(aq) ¾® CaSO4(s) + CO2(g) + H2O (i) (c) The chemical reaction between MnO2 and HCl is Hence, option (c) is correct. redox reaction. (v). (d) Calcium oxide can be reduced to calcium by Oxidation heating with sodium metal and calcium oxide acts as an oxidising agent because it oxidises other (Gain of O-atoms) substance, i.e. sodium and its gets reduced. MnO2 + 4HCl MnCl2 + 2H2O + Cl2 2. Read the following and answer any Reduction four questions from (i) to (v). (Loss of O-atoms) The reaction between MnO2 with HCl is depicted in the following diagram. It was Hence, option (c) is correct. observed that a gas with bleaching abilities was released . (ii) (a) Chlorine gas reacts with dry Ca(OH)2 to form bleaching powder. HCl (aq) Ca(OH)2 + Cl2 ¾® Ca(OCl)2 + H2O MnO2(s) (Bleaching power) Reactants Products Hence, option (a) is correct. (iii) (a) MnO2 + 4HCl ¾® MnCl2 + 2H2O + Cl2 ­ CBSE QUESTION BANK (i) The chemical reaction between MnO2 and HCl is an example of In this reaction, MnO2 is getting reduced to MnCl2 by (a) displacement reaction losing oxygen atoms, while HCl is getting oxidised to H2O by gaining oxygen atom. (b) combination reaction Hence, option (a) is correct. (c) redox reaction (iv) (b) The nature of MnO2 is basic oxide. MnO2 has the lowest state of oxidation. (d) decomposition reaction Hence, option (b) is correct. (ii) Chlorine gas reacts with…… to form (v) (b) If we take dry HCl gas instead of aqueous bleaching powder. solution of HCl, then no reaction takes place. MnO2 + HCl (dry gas) ¾® reaction will not occur. (a) dry Ca(OH)2 Hence, option (b) is correct. (b) dil. solution of Ca(OH)2 (c) conc. solution of Ca(OH)2 3. Read the following and answer any (d) dry CaO four questions from (i) to (v). (iii) Identify the correct statement from the following ; Frothing in Yamuna : The primary reason behind the (a) MnO2 is getting reduced whereas HCl formation of the toxic foam is high is getting oxidised. phosphate content in the waste water because of detergents used in dyeing industries, dhobi ghats and households. Yamuna’s pollution level is so bad that parts of it have been labelled ‘dead’ as

CBSE Sample Paper Science Class X (Term I) 39 there is no oxygen in it for aquatic life to (a) P > Q > R > S (b) P > S > Q > R survive. (c) S < Q < R < P (d) S < P < Q < R (iv) High content of phosphate ion in river Yamuna may lead to (a) decreased level of dissolved oxygen and increased growth of algae. (b) decreased level of dissolved oxygen and no effect of growth of algae. (c) increased level of dissolved oxygen and increased growth of algae. (d) decreased level of dissolved oxygen and decreased growth of algae. (i) Predict the pH value of the water of river (v) If a sample of water containing detergents is provided to you, which of the following Yamuna if the reason for froth is high methods will you adopt to neutralise it? (a) Treating the water with baking soda content of detergents dissolved in it. (b) Treating the water with vinegar (c) Treating the water with caustic soda (a) 10-11 (b) 5-7 (d) Treating the water with washing soda (c) 2-5 (d) 7 Sol. (ii) Which of the following statements is (i) (a) If high content of detergent dissolved in water of correct for the water with detergents dissolved in it? river Yamuna then the value of pH of water will be (a) Low concentration of hydroxide ion (OH-) and high concentration of 10-11. Because nature of detergent is basic. So, hydronium ion (H3O+ ). water becomes basic and pH of basic water may be (b) High concentration of hydroxide ion (OH-) and low concentration of 7-14. Hence, correct option is (a). hydronium ion (H3O+ ). (ii) (b) Almost all detergents have NaOH which is basic (c) High concentration of hydroxide ion in nature and gives OH- ion in water. When they (OH-) as well as hydronium ion (H3O+ ). dissolved in water then the concentration of hydroxide ion (OH-) increases and the concentration (d) Equal concentration of both hydroxide of hydronium ion (H3O+ ) decreases. ion (OH-) and hydronium ion (H3O+ ). (iii) (c) The value of pH of solution depends on hydronium ion concentration. Lower the value of pH it means higher the hydronium ion concentration. (iii) The table provides the pH value of four Hence, according to given pH values the increasing solutions P, Q, R and S. order of hydronium ion concentration will be S < Q < R < P. (11 < 9 < 5 < 2). Solutions pH value (iv) (a) Phosphorus is an essential element for plant life but when there is too much of it in water, it can speed P2 up eutrophication (a reduction in dissolved oxygen in water bodies caused by an increase of mineral and Q9 organic nutrients) of river and lakes. A sign of this is excess algae in the lake. R5 S 11 (v) (b) Detergents are basic in nature. Which of the following correctly represents So, for neutralise it, acid is required. Because vinegar CBSE QUESTION BANK the solutions in increasing order of their is an acid, it can neutralise detergents. Hence, option hydronium ion concentration? (b) is correct.

40 CBSE Sample Paper Science Class X (Term I) Latest CBSE SAMPLE PAPER Latest Sample Question Paper for Class X (Term I) Issued by CBSE on 2 Sept 2021 Science Class 10 (Term I) Maximum Marks : 40 Time allowed : 90 Min. Instructions (i) This paper is divided into three Sections: (a) Section A – Contains 24 questions. Attempt Attempt any 20 questions. (b) Section B – Contains 24 questions. Attempt Attempt any 20 questions. (c) Section C – Contains 12 questions. Attempt Attempt any 10 questions. (ii) Each questions carries 0.80 mark. (iii) There is NO negative marking. Roll No. Section A Section-A consists of 24 questions. Attempt any 20 questions from this section. The first attempted 20 questions would be evaluated. 1. Reema took 5 mL of lead nitrate solution in a beaker and added approximately 4 mL of potassium iodide solution to it. What would she observe? (a) The solution turned red (b) Yellow precipitate was formed Latest CBSE SAMPLE PAPER (c) White precipitate was formed (d) The reaction mixture became hot 2. Identify gas A in the following experiment. Thistle funnel Delivery tube Burning of gas A Stand with a pop sound Bubbles Test tube of gas A Candle Dilute Soap bubble filled sulphuric with gas A acid Zinc granules Soap solution (a) Nitrogen (b) Hydrogen (c) Oxygen (d) Carbon dioxide

CBSE Sample Paper Science Class X (Term I) 41 3. METAL Dil.HCl METAL GAS SALT Which of the following two combinations are correct ? Metal Gas evolved (i) Copper Yes (ii) Iron Yes (iii) Magnesium No (iv) Zinc Yes (a) (i) and (iii) (b) (i) and (iv) (c) (ii) and (iii) (d) (ii) and (iv) 4. Which of the following correctly represents a balanced chemical equation ? (a) Fe(s) + 4H2 O (g) ¾® Fe3 O4 (s) + 4H2 (g) (b) 3Fe(s) + 4H2 O (g) ¾® Fe3 O4 (s) + 4H2 (g) (c) 3Fe(s) + H2 O (g) ¾® Fe3 O4 (s) + H2 (g) (d) 3Fe(s) + 4H2 O (g) ¾® Fe3 O4 (s) + H2 (g) 5. The graph given below depicts a neutralisation reaction (acid + alkali ® salt + water). The pH of a solution changes as we add excess of acid to an alkali. A B 14 pH C value 7 D 0 Volume of acid added Which letter denotes the area of the graph where both acid and salt are present? (a) A (b) B Latest CBSE SAMPLE PAPER (c) C (d) D 6. In the reaction of iron with copper sulphate solution, CuSO 4 + Fe ¾® Cu + FeSO 4 Which option in the given table correctly represents the substance oxidised and the reducing agent ? Substance oxidised Reducing agent (a) Fe Fe (b) Fe FeSO4 (c) Cu Fe (d) CuSO4 Fe

42 CBSE Sample Paper Science Class X (Term I) 7. The chemical reaction between copper and oxygen can be categorised as (a) displacement reaction (b) decomposition reaction (c) combination reaction (d) double displacement reaction 8. Which of the given option correctly represents the parent acid and base of calcium carbonate? Parent acid Parent base (a) HCl NaOH (b) H2CO3 Ca(OH)2 (c) H3PO3 CaSO4 (d) H2SO4 CaSO4 9. How will you protect yourself from the heat generated while diluting a concentrated acid ? (a) By adding acid to water with constant stirring (b) By adding water to acid with constant stirring (c) By adding water to acid followed by base (d) By adding base to acid with constant stirring 10. Why is it important to balance a skeletal chemical equation? (a) To verify law of conservation of energy (b) To verify the law of constant proportion (c) To verify the law of conservation of mass (d) To verify the law of conservation of momentum 11. Carefully study the diagram of the human respiratory system with labels (i), (ii), (iii) and (iv). Select the option which gives correct identification and main function and /or characteristic. (i) Latest CBSE SAMPLE PAPER Bronchus Cut end of rib heart (ii) Lung (iii) (iv) (a) (i) Trachea: It is supported by bony rings for conducting inspired air (b) (ii) Ribs: When we breathe out, ribs are lifted (c) (iii) Alveoli: Thin walled sac-like structures for exchange of gases (d) (iv) Diaphragm: It is pulled up when we breathe in

CBSE Sample Paper Science Class X (Term I) 43 12. Identify the option that indicates the correct enzyme that is secreted in location (i), (ii) and (iii). (i) (ii) (iii) (a) (i)-Lipase, (ii)-Trypsin, (iii)-Pepsin Latest CBSE SAMPLE PAPER (b) (i)-Amylase, (ii)-Pepsin, (iii)-Trypsin (c) (i)-Trypsin, (ii)-Amylase, (iii)-Carboxylase (d) (i)-Permease, (ii)-Carboxylase, (iii)-Oxidase 13. Opening and closing of stomatal pore depends on (a) atmospheric temperature (b) oxygen concentration around stomata (c) carbon dioxide concentration around stomata (d) water content in the guard cells 14. The figure given below shows a schematic plan of blood circulation in humans with labels. Identify the correct label with its functions. (iii) (i) (iv) (ii) (a) (i) Pulmonary vein - takes impure blood from body parts (b) (ii) Pulmonary artery - takes blood from lungs to heart (c) (iii) Aorta - takes blood from heart to body parts (d) (iv) Vena cava - takes blood from body parts to right auricle