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2. Give an example of how an enzyme is used in industrial processes. Enzymes (yeast) - fermentation

3. Give an everyday use of an enzyme. Biological washing powders, dishwasher tablets

4. What is an enzyme? A biological catalyst. They catalyse reactions which take place in the living cells of plants and animals.

5. Why do cars with catalytic converters use lead free petrol. To prevent the lead poisoning the catalyst.

6. Why are cars fitted with catalytic converters ? The convert harmful gases into less harmful gases.

7. Name two toxic gases produced in a car engine. What does a catalytic converter change them to? Carbon monoxide is converted to carbon dioxide. Oxides of nitrogen are converted to nitrogen.

8. What can reduce the surface activity of a catalyst? Poisoning

9. What name is given to a catalyst which is in the same state as the reactants? Homogeneous

10. What is meant by a heterogeneous catalyst? The catalyst is in a different state than the reactants

11. What is a catalyst? A substance which - speeds up a chemical reaction is not used up by the reactions

12. How can the course of a reaction be followed? By measuring changes in - -concentration -mass -volume of reactants and products.

13. How is the average rate of a reaction calculated? change in quantity change in time

14. In a reaction, 60cm 3 of gas were collected in 20 s. Calculate the average rate of the reaction, in cm 3 s -1, in the first 20 s. Change in quantity = 60 change in time = 20 60/20 = 3.

15. How is the rate of a reaction calculated? Rate = 1/time 1/t Time = 1/rate

16. Use the graph to find the time taken, in seconds, when the experiment was carried out using 0.1 mol -1 sodium hydroxide solution. From the graph the rate = 0.02 Time is 1/rate1/0.02 = 50

17. What factors can affect the rate of a reaction? Concentration Temperature Particle size Use of a catalyst

18. How can changes in concentration, temperature, particle size and use of a catalyst affect the rate of a reaction? Increase concentration - increase rate Increase temperature - increase rate ( except when using an enzyme ) Decrease particle size - increase rate Use of catalyst - increase rate

19. Explain how concentration affects the rate of the reaction in terms of the collision theory. Concentration increases - more particles to collide - more successful collisions - increased rate of reaction

20. Explain how particle size affects the rate of the reaction in terms of the collision theory. Particles become smaller - surface area increases - more successful collisions - increased rate of reaction

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