Sci7_Q1_M5B_Contration-Of-Sultions_version3

7 SCIENCE CFoirnstcQeuanrtterr,aMtoidounle 5oBf ConcenStroaltuiotnioonf Ssolutions Fi(rPsterQcueanrttebry, MVoodluumle e5)B 90% 78% 68% 50% 42% Department of Education ● Republic of the Philippines 1

What I Know Before starting with this module, let us see what you already know about concentration of solutions. Directions: Read each questions carefully. Choose the letter that corresponds to the correct answer. 1. Alcohol is a widely used disinfectant in this pandemic. A solution of 65% ethyl or isopropyl alcohol is enough to destroy the virus. How much alcohol is present in a 100 mL solution? A. 60 mL B. 65 mL C. 70 mL D. 75 mL 2. What is the concentration, in percent by mass, of 0.85 g of solute in 50.0 g of solution? A. 0.14 % B. 1.38% C. 1.41% D. 1.70 % 3. A beverage contains 9% alcohol which means that ____________ A. the solution contains 100 mL of alcohol in 100 mL of water. B. the solution contains 3 mL of alcohol in 97 mL of water. C. the solution contains 9 mL of alcohol in 91 mL of water. D. the solution contains 300 mL of alcohol in 700 mL of water. 2

4. What is the percent by volume of ethanol in a solution that contains 23 milliliters of ethanol dissolved in 1 liter of water? A. 0.23% B. 2.30% C. 23.30% D. 25.00% 5. What is the percent by volume of isopropyl alcohol in a solution that contains 400 mL of isopropyl alcohol in 2.3 L of water? A. 1.20% B. 2.10% C. 12.20% D. 17.39% 6. What is the concentration, if a solution is prepared by dissolving 90 mL of hydrogen peroxide in enough water to make 3000 mL of solution? A. 2 % B. 3 % C. 4 % D. 5 % 7. If you have 30% of a 100 milliliters of an aqueous solution of ethanol, what volumes of ethanol and water are in the solution? A. volume of ethanol= 30 mL, volume of water = 70 mL B. volume of water = 30 mL, volume of ethanol =70 mL C. volume of ethanol = 30 mL volume of water = 80 mL D. volume of ethanol = 32 mL, volume of water = 68 mL 3

8. What is the percent by volume of isopropyl alcohol in a solution that contains 850 mL of isopropyl alcohol in 2.8 L of water? A. 23.29 % B. 25.88 % C. 25.97 % D. 28.33 % 9. Vinegar is a solution with 5% acetic acid as a solute. How much acetic acid does it contain in a 1L solution? A. 5 mL B. 25 mL C. 50 mL D. 75 mL 10. Methanol is an alcohol common to alcoholic beverages but toxic if it contains more than 0.4%. How much methanol is present in a 750 mL solution? A. 3 mL B. 4 mL C. 5 mL D. 6 mL 4

Lesson Concentration of Solutions 2 What’s In When you add a small amount of sugar to water, the solid disappears. We say that it __________. The water particles are attracted to the _______ particles. Although the sugar particles are still there, we can’t see them anymore. Sugar is soluble in water and has formed a solution. When there is a solid solute and liquid solvent, we use percent by _________. What’s New CoVID 19 pandemic enables most individual to make homemade disinfectants. Name three solutions which are trendy during this pandemic. What is it? Percent by volume are for solutions that involve a liquid solute and solvent, and expresses concentration by volume of its components. It expresses the concentration of a liquid solution as percentage of the volume of solute to the volume of the solution (g/100 mL). Most rubbing alcohol products sold in this pandemic have a concentration of 70%, which could be isopropyl or ethyl alcohol. 5

This means that 70% is alcohol and the other 30% is water (by volume of solute and solvent). Percent by volume could be computed as: Volume of solute % Volume = x 100% Volume of solution TAKE The volume of the solute, NOTE solvent and solution must be expressed in the same units. However, there are instances when the volume of the solutions is not equal to the volume of the solvent and solute; this is because the volume of the liquid is not absolutely proportionate. ExaSmApMlePs:LE EXERCISES 1. Most alcoholic beverages contain ethanol (ethyl alcohol). A 750 mL bottle of wine contains 93.75 mL of ethanol. What is the percent by volume concentration of ethanol in the bottle? Given: Volume of solute = 93.75 mL Identify the given quantities. Volume of solution = 750 mL Asked: % Volume = ? Know what’s being asked. Choose applicable equation. Solution: % Volume = Volume of solute x 100% Volume of solution % Volume = 93.75 mL x 100% Substitute the given quantities 750 mL and cancel same units % Volume = 0.125 x 100% Multiply result by 100 % Volume = 12.50% Make sure you have the correct unit. 6

2. How many milliliters of ethyl alcohol are present in a 50 mL bottle of a 70% alcohol solution? Given: % Volume = 70 % Identify the given quantities. Volume of solution = 50 mL Asked: Know what’s being asked. Volume of solute = ? Solution: Since the given is a 70% alcohol solution. It means that 100 mL of the alcohol solution contains 70 mL ethyl alcohol. Volume of solute = % Volume x Volume of solution Derive the percent by volume equation 100% to volume solute Volume of solute = 70 % x 50 mL Substitute the given quantities 100% and cancel same units Volume of solute = 0.70 x 50 mL Multiply result with volume of solution Volume of solute = 35.00 mL Make sure you have the correct unit. 7

is What’s More Directions: Solve the following problems. Show your solutions and express your answer in two decimal places. Write your answer in your notebook. 1. Boric acid is said to be soluble to water. How will you prepare 50 mL solution that is 2% boric acid? 2. What is the percent by volume of a 90mL solution that contains 25 mL methanol? What I Have Learned Concentration of solutions that involves liquid solute and solvent uses ____________________ with an equation: Volume of ________ % Volume = x _____ Volume of _________ What I Can Do The present pandemic makes us more conscious and adherent to disinfecting our surroundings. A lot of it are commercially available and are out of stock due to high demand. A concentration of at least 60% alcohol by volume is enough to destroy most viruses including coronavirus. A 100% (anhydrous) alcohol has serious side effects, including headache, nausea, vomiting and irritation of the nasal passages and lungs, and may cause loss of consciousness. 8

Given the recent situation, and you were provided with an ethyl alcohol (ethanol) solution and a 20 mL medicine cup. How would you prepare a 1.5 L solution with 60% ethyl alcohol concentration? Anhydrous alcohol Medicine cup 1.5 L container Figure 1.Materials for preparing ethyl alcohol 9

Assessment Now, that you are finished accomplishing the module, let us check what you have learned. Answer the questions and write your answers in your science notebook. 1. Alcohol as disinfectant is normally sold as a solution of 70% ethyl or isopropyl alcohol. How much alcohol is present in a 100 mL solution? A. 30 mL B. 60 mL C. 70 mL D. 75 mL 2. A beverage contains 3% alcohol which means that ______________ A. The solution contains 30 mL of alcohol. B. The solution contains 30 mL water in 70 mL of water. C. The solution contains 3 mL of alcohol in 97 mL of water. D. The solution contains 300 mL of alcohol in 700 mL of water. 3. What is the percent by volume of ethanol in a solution that contains 35 milliliters of ethanol dissolved in 115 milliliters of water? A. 0.23% B. 2.33% C. 23.33% D. 25.00% 4. What is the percent by volume of isopropyl alcohol in a solution that contains 24 mL of isopropyl alcohol in 1.1 L of water? A.1.20% B. 2.18% C. 2.22% D. 12.21% 10

5. Nail polish is said to have varnish as a solute and propanone as a solvent. How much propanone is present in 50% concentration of 150 mL solution? A. 50 mL B. 55 mL C. 70 mL D. 75 mL 6. Antifreeze is an additive to lower freezing point which is compose of ethylene glycol and water and is said to have 50% composition. How much solute and solvent is present? A. In 100 mL, ethylene glycol is 50 mL and water is 75 mL. B. In 2 L, ethylene glycol is 1000 mL and water is 1000 mL. C. In 1.5 L, ethylene glycol is 1000 mL and water is 500 mL. D. In 20.5 L, ethylene glycol is 10200 mL and water is 10300 mL 7. Vinegar is said to contain 5% acetic acid. How much water is present in a 500 mL solution? A. 25 mL B. 250 mL C. 332 mL D. 475 mL 8. Povidone iodine is a 10% antiseptic solution. In a 120 mL solution, how many mL of iodine is present? A. 12 mL B. 15 mL C. 18 mL D. 21 mL 11

For Items 9 – 10, refer to the given problem below. A 150 mL agua oxygenada solution is found to contain 0.75 mL hydrogen peroxide, 2.55 mL lactic acid, 0.75 mL dodecyl benzene sulfonic acid and 145.95 mL of inert ingredients. 9. What is the percent by volume of hydrogen peroxide? A. 0.5 % B. 1.7 % C. 3.6 % D. 97.3 % 10. What is the percent by volume of lactic acid? A. 0.5 % B. 1.7 % C. 3.6 % D. 97.3 % 12

Additional Activity (Optional) Do me! Dis-infect. Important notes: Please do this activity under your teacher’s supervision. Keep in mind the safety precaution when using liquids that are skin irritant and with irritant odor. Objective: To prepare a solution for disinfection at home. Materials: Bleach (Sodium hypochlorite) Water 1 Liter container Procedure: A. Most household bleach solutions contain 5% sodium hypochlorite (50,000 ppm* available chorine) B. 1:100 dilution of 5% sodium hypochlorite is the usual recommendation. Use 1 part bleach to 99 parts cold tap water (1:100 dilution) for disinfection of surfaces. Adjust ratio of bleach to water as needed to achieve appropriate concentration of sodium hypochlorite, e.g. for bleach preparations containing 2.5% sodium hypochlorite, use twice as much bleach (i.e. 2 parts bleach to 98 parts water). C. Compute the parts of solute (bleach) and solvent (water) to be added to yield a total volume of 1 L (1000 mL). D. Place your solution in a 1L container. E. Disinfect by wiping surfaces: a contact time of ≥10 min is recommended. 13

Precautions for the use of bleach: 1. Bleach can corrode metals and damage painted surfaces. 2. Avoid touching the eyes. If bleach gets into the eyes, immediately rinse with water for at least 15 minutes, and consult a physician. 3. Bleach should not be used together with, or mixed with, other household detergents because this reduces its effectiveness and can cause chemical reactions. 4. A toxic gas is produced when bleach is mixed with acidic detergents, such as those used for toilet cleaning, and this gas can cause death or injury. If necessary, use detergents first, and rinse thoroughly with water before using bleach for disinfection. 5. Undiluted bleach liberates a toxic gas when exposed to sunlight and should be stored in a cool and shaded place. 6. Sodium hypochlorite decomposes with time. To ensure its effectiveness, purchase recently-produced bleach, and avoid over- stocking. 7. Diluted bleach should be made fresh daily, labeled, dated, and unused portions discarded 24 hours after preparation. 8. Organic materials inactivate bleach; surfaces must be cleaned of organic materials before disinfection with bleach. 9. Keep diluted bleach covered, protected from sunlight, in a dark container (if possible), and out of the reach of children. https://www.ipswichma.gov/DocumentCenter/View/10072/50ppm- Guidelines-on-the-Use-of-Disinfectants 14

What I Know What I Have LearnedAnswer Key 1. B Concentration of solutions that involves liquid15 2. D 3. C solute and solvent uses percent by volume with 4. B 5. D an equation: 6. B 7. A volume of solute x 100% 8. A % volume = 9. C 10. A volume of solution What’s In n What I can do Compute the volume of alcohol in the solution, which is equal to 900 When you add a small mL and divide it by 20 mL giving amount of sugar to water, the solid disappears. We say that it dissolved. 45 cups of alcohol that should be The water particles are attracted to the sugar particles. Although the sugar added to make a 60% 1.5L particles are still there, we can’t see solution. Assessment them anymore. Sugar is soluble in water 1. C and has formed a solution. When there 2. C is a solid solute and liquid solvent, we 3. B use percent by volume 4. B 5. D What’s More 6. B 7. A 1. 1.00 mL Boric acid added to a 8. A 49.00 mL water 9. A 10. B 2. 27.78 % methanol