Rr

Rate of Reaction

Factors What Collision affecting? is ? theory? Rate of reaction Activation Energy level energy? diagram? Effective collision?

What is the rate of a reaction The rate of reaction is how quickly the reaction happens. Fast Slow reaction reaction

Iron rusting - a Wood burning - CHEMICAL a CHEMICAL REACTION REACTION with with a slow a fast reaction reaction rate. rate.

Rate of Reaction



Measuring Reactant & Product •Solids Measuring mass •Gas Measuring volume •Solution Measuring concentration

























Time (s) 0 10 20 30 40 50 Volume of gas (dm3) 0 0.12 0.16 0.20 0.22 0.22 1. when did the reaction stop. 2. what was the rate of reaction. 3. What is the rate of reaction at 10 – 50 s ? 4. What is the rate of reaction at 20 – 40 s ?

• The initial rate of production of Br2 gas in the following reaction is 0.0750 mol/(L.s). What is the rate of loss of HBr gas? 4HBr(g) + O2(g) ⇒ 2Br2(g) + 2H2O(g)

• An experiment is performed by displacement of water to determine the rate of the following reaction: • Zn(s) +2HCl(aq) H2(g) + ZnCl2(aq) Calculate the average rate of formation of H2 in mL/s for the time interval between 20 and 40 seconds.

• Consider the reaction: A + 2B 3C • If the rate of consumption of A is 5.6 × 10– 3 mol/s, what are the rates of B and C?

• Consider the following reaction: C12H22O11(s) 11H2O(g) + 12C(s) • The rate of decomposition of C12H22O11 is 0.75 mol/min. What mass of C is produced in 10.0seconds?

• Consider the reaction: 2H2O(l) 2H2(g) + O2(g) • The rate of production of O2 is 1.2 × 10–2 mol/s . How many seconds will it take to decompose 100.0 g H2O?

• Consider the reaction: • 2Al(s) + 6HCl(aq) 2AlCl3(aq) + 3H2(g) • A 10.0 g sample of Al reacts completely in excess HCl in 300.0 s. What is the rate of production of H2 in g/s ?

Factors What Collision affecting? is ? theory? Rate of reaction Activation Energy level energy? diagram? Effective collision?

collision theory \"You can’t react if you don’t collide.\"

3 necessary requirements in order for a reaction to take place: 1. the molecules must collide to react. If two molecules simply collide, however, they will not always react; therefore, the occurrence of a collision is not enough.

2. there must be enough energy (energy of activation) for the two molecules to react. This is the idea of a transition state; if two slow molecules collide, they might bounce off one another because they do not contain enough energy to reach the energy of activation and overcome the transition state (the highest energy point).

3. the molecules must be oriented with respect to each other correctly. For the reaction to occur between two colliding molecules, they must collide in the correct orientation, and possess a certain, minimum, amount of energy.

Collision Theory • In order to react molecules and atoms must touch each other. • They must hit each other hard enough to react. • Anything that increase these things will make the reaction faster.

collision theory • chemical reaction only occur between partic leswhen they collide •There is a minimum amount of energy which colliding particles need in order to react •If the colliding particles have less than this minimum energythen they just bounce off each other and no reaction occurs. This minimum energy is called the activation energy.

Factors What Collision affecting? is ? theory? Rate of reaction Activation Energy level energy? diagram? Effective collision?

Prevent Effective collision Camera to detect fast moving traffic

NOT Effective collision NO3(gas) + CO(gas) ➔ NO2(gas) + CO2(gas) Reactants Molecules moving too bounce ( no slowly reaction)

NOT Effective collision NO3(gas) + CO(gas) ➔ NO2(gas) + CO2(gas) Reactants Molecules not facing bounce ( no right way reaction)

Effective collision Reactants energy is Reaction high & oriented happens right way

Effective collision The orientation of collision

Effective collision

Effective collision Which collision is effective?

Factors What Collision affecting? is ? theory? Rate of reaction Activation Energy level energy? diagram? Effective collision?

Activation energy •The energy that must be overcome in order for a chemical reaction to occur •Activation energy is the minimum energy necessary for a specific chemical reaction to occur •For chemical reaction to have noticeable rate, there should be noticeable number of molecules with the energy equal or greater than the activation energy.

Activation energy The sparks generated by striking steel against a flint provide the activation energy to initiate combustion in this Bunsen burner

What is activation energy A little activation energy is added with the aid of a weed burner...

What is activation energy Not enough A \"hot\" reaction in kinetic energy progress showing for reactants to reactants leaping leap over over the activation reaction barrier. energy barrier

Activation energy

Activation energy

What is activation energy Only collisions with enough energy react to form products. The critical amount of energy to make the reaction proceed

A + B →C+D reactants products