11 22 33 44 55

66 77 88 99 1010

1111 1212 1313 1414 1515

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17171616

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

3. Work out the rate of reaction over the first 20 seconds.

Rate = Rate = Change in ConcentrationChange in Concentration

Change in TimeChange in Time

= = (0.2 – 0.05)(0.2 – 0.05)

(20 – 0)(20 – 0)

== 0.15 0.15 = 0.0075 mol /l / s = 0.0075 mol /l / s

2020

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mol

/ l

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4. Describe how particle size affects the speed of reaction?

As particle size decreases theAs particle size decreases the

speed of reaction increasesspeed of reaction increases

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5. Describe how temperature affects the speed of reaction?

As temperature increases the As temperature increases the speed of reaction increasesspeed of reaction increases

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6. What are ENZYMES?

Biological catalystsBiological 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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9. Work out the rate of reaction between 20 and 40 seconds.

Rate = Rate = Change in VolumeChange in Volume

Change in TimeChange in Time

= = (41 – 29)(41 – 29)

(40 – 20)(40 – 20)

== 12 12

2020

= 0.6 cm= 0.6 cm33 / s / s

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10.10. What must be controlled when What must be controlled when carrying out experiments to carrying out experiments to compare compare

speeds of reaction?speeds of reaction?

All variables other than the All variables other than the one being tested must be one being tested must be

kept the same in all kept the same in all experimentsexperiments

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11. What is a VARIABLE?

Any factor in an experiment Any factor in an experiment which can be changed or varied. which can be changed or varied. e.g. concentration or temperaturee.g. concentration or temperature

of the solution usedof the solution used

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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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2M hydrochloric acid at 250C

2M hydrochloric acid at 250C

2g of large chalk lump

2g of small chalk lumps

A2M hydrochloric

acid at 150C

2g of small chalk lumps

B

C1M hydrochloric

acid at 250C

2g of small chalk lumps

Dansweranswer

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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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2M hydrochloric acid at 250C

2g of small chalk lumps

A2M hydrochloric

acid at 150C

2g of small chalk lumps

B

2M hydrochloric acid at 250C

2g of large chalk lump

C1M hydrochloric

acid at 250C

2g of small chalk lumps

Dansweranswer

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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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2M hydrochloric acid at 250C

2g of small chalk lumps

A2M hydrochloric

acid at 150C

2g of small chalk lumps

B

2M hydrochloric acid at 250C

2g of large chalk lump

C1M hydrochloric

acid at 250C

2g of small chalk lumps

Dansweranswer

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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).