This document discusses average and instantaneous rates of reaction and how to determine them from a graph. It also discusses collision theory and how factors like temperature, concentration, particle size, and catalysts affect the rate of a reaction according to this theory. Collision theory states that for a reaction to occur particles must collide with enough energy to overcome the activation energy barrier. These factors influence the rate by increasing the frequency and effectiveness of collisions between reacting particles.

1. HOW TO DETERMINE RATE OF REACTION FROM GRAPH AVERAGE RATE OF REACTION INSTANTANEOUS RATE OF REATION

2. AVERAGE RATE OF REACTION For the whole exp From X min to Y min On the X min (2 nd ) ( from 2 nd to 1 st ) For first x (3) min ( from 0 to 3rd )

3. INSTANTANEOUS RATE OF REACTION ( rate of reaction at that time) Draw tangent to the graph Y X Rate = Y/X

4. b) Example from the graph, determine: i) The rate of reaction at 120 s Instantaneous rate of reaction = Draw tangent to the graph

5. = 56 – 20 = 0.176 cm 3 s -1 222-18

6. Changes to the graph

7. Changes to the CURVE part of graph II I III Volume of gas Time Use negative catalyst Decrease temperature Decrease TSA Use positive catalyst Increase temperature Increase total surface area

8. Changes to the FLAT part of graph

9. d) Curve I represents the result of the experiment using excess zinc powder and 50cm 3 of 1.0 moldm -3 dilute hydrochloric acid II I III Volume of gas/ cm 3 Time/s Use positive catalyst Increase temperature of reactant Lower concentration of hydrochloric acid

10. Collision theory Theory that explains how factors affect rate of reaction Before reaction can occur, particles must first collide Particles collide so that bonds are broken and new bonds can form

11. Collision theory Collision of particles must be effective collisions to produce result Effective collisions are collisions which produce enough energy to overcome energy of activation correct orientation

12. Collision theory Activation energy is the minimum energy the colliding particles must overcome so that reaction occur In order for particles to overcome the activation energy, several factors involve

13. How factors affect rate of reaction according to collision theory Size of reactant for solid reactant Temperature of reactant mixture Concentration of solution reactant Presence of catalyst

14. How Collision theory explain factor of size of solid reactant The smaller the size of reactant , the larger the total surface area Frequency of Collisions between particles increase Frequency of Effective collisions between particles increase Therefore rate of reaction also increase

15. How Collision theory explain factor of concentration The higher the concentration of reactant solution , the higher the number of particles per unit volume Frequency of Collisions between particles increase Frequency of Effective collisions between particles increase Therefore rate of reaction also increase

16. How Collision theory explain factor of temperature The higher the temperature of reactant solution , the higher the kinetic energy of particles Frequency of Collisions between particles increase Frequency of Effective collisions between particles increase Therefore rate of reaction also increase

17. Collision theory explain factor of catalyst Presence of catalyst provide an alternative path This alternative path has a lower activation energy More colliding particles can overcome this lower activation energy Frequency of Effective collisions between particles increase Therefore rate of reaction also increase