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Rates of Reaction 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
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1. Describe how the concentration of reactants affects the speed of reaction?
As the reactant concentration increases the speed of the reaction increases.
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2. Name FOUR factors which affect the speed (or rate) of a chemical reaction?
Particle Size (Surface Area)
Temperature
Concentration
Use of Catalyst
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3. Draw a line to show the results if a higher temperature is used with the exact same chemicals?
Steeper gradient
Same final result (volume)
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5. 4. Describe how particle size affects the speed of reaction?
As particle size decreases the
speed of reaction increases
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6. 5. Describe how temperature affects the speed of reaction?
As temperature increases the speed of reaction increases
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6. What are ENZYMES?
Biological catalysts
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7. What is a catalyst?
A substance which can speed up a reaction, but is not used up in the reaction and can be recovered chemically unchanged
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8. Why does decreasing the particle size of reactants increase the speed of reaction?
Smaller particles give a bigger surface area. This results in more collisions between reactants and therefore faster reactions
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10. 9. What time did the reaction finish at?
45 seconds
(when the line flattens out and no more gas is produced)
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10. What must be controlled when carrying out experiments to compare speeds of reaction?
All variables other than the one being tested must be kept the same in all experiments
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11. What is a VARIABLE?
Any factor in an experiment which can be changed or varied. e.g. concentration or temperature
of the solution used
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13. 12. Give everyday examples of uses of catalysts?
Transition metals in car catalytic converters.
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13. Rates Experiments
Which two of the following experiments could be used to find the effect of changing the particle size?
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15. 2M hydrochloric acid at 150C
2g of small chalk lumps A
2M hydrochloric acid at 150C
2g of small chalk lumps B
2M hydrochloric acid at 250C
answer
1M hydrochloric acid at 250C
2g of small chalk lumps D C
2g of large chalk lump
2M hydrochloric acid at 250C
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14. Rates Experiments
Which two of the following experiments could be used to find the effect of changing the concentration of the acid?
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17. A B C D answer 2M hydrochloric acid at 250C 2g of small chalk lumps
2g of large chalk lump C
1M hydrochloric acid at 250C
2g of small chalk lumps D
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15. Rates Experiments
Which two of the following experiments could be used to find the effect of changing the temperature of the acid?
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19. A B D C answer 2M hydrochloric acid at 250C 2g of small chalk lumps
2g of large chalk lump C
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20. 16. What does EXOTHERMIC mean?
Heat energy is given out in a reaction.
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17. Two chemical react in a test tube. The temperature goes down. Is the reaction EXOTHERMIC or ENDOTHERMIC?
ENDOTHERMIC
(heat energy is taken in by the reaction, this makes the surrounding temperature fall).
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22. 18. Which colour of line shows the fastest rate of reaction?
RED LINE
Steeper gradient
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19. What could you measure in this experiment to work out the rate of reaction? Marble + Acid  Salt + Water + Carbon dioxide
Change in mass
Volume of gas produced
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