p3. the rate and extend of chemical change

Question 1

how to calculate mean rate of reaction

Answer 1

                            time taken

Question 2

factors which affect rate of reaction and how they affect it

Answer 2

• concentration of reactants- higher = faster
• surface area of a solid - bigger = faster
• temperature - higher = faster
• catalysts - present = faster

Question 3

what is the collision theory?

Answer 3

• for a chemical reaction to occur
• need successful collisions ( correct orientation )
• need activation energy = minimum amount of energy needed for a successful collision

Question 4

how does concentration affect collision theory / rate of reaction

Answer 4

• increase concentration = increases rate of reaction
• reactant particles become more crowded
• more frequent successful collisions

Question 5

how does surface area affect collision theory / rates of reaction

Answer 5

• increase surface area = increases rate of reaction
• more reactant particles are more exposed at surface
• more frequent successful collisions

Question 6

how does temperature affect collision theory / rates of reaction

Answer 6

• increase temperature = increases rate of reaction
• particles move quicker
• energy of particles increase
• more frequent successful collisions

Question 7

how do catalysts affect collision theory / rates of reaction

Answer 7

• catalysts increase rate of reaction without using up products of reaction
• catalyst present = increases rate of reaction
• provides different pathway for reaction that has a lower activation energy

Question 8

RP. measure the production of a gas

Answer 8

1. support gas syringe with stand,boss and clamp
2. using measuring cylinder,add 50ml of dilute hydrochloric acid to conical flask
3. add 0.4g of calcium carbonate to flask. connect gas syringe and start stop watch
4. every 10 seconds record volume of gas produced
5. when reaction is complete,clean apparatus
6. repeat steps 1-5 with different concentrations of hydrochloric acid