Test
Rates of Reactions
Preguntas del test (7)
1An increase in temperature increases the rate of reaction. Why?
How many of these are correct explanations.
- The particles move faster because they have more energy.
- Particles collides more often.
- There are more particles per unit volume, resulting in more collisions.
- More of the collisions between particles are successful because they have more energy (have the activation energy).
- Rate of reaction increases because there is an increase in the frequency of collisions. /- A2
- B3
- C4
2Increasing the concentration of the reactant increases the rate of the reaction. Why?
How many of these are correct explanations.
- Rate of reaction increases because the particles move faster and collide more.
- Rate of reaction increases because there are more particles per unit volume.
- Rate of reaction increases because there is an increase in the frequency of collisions.
- Rate of reaction increases because the particles have more energy.- A2
- B3
- C1
3What is the effect of increasing the pressure on the rate of reaction?
- ARate of reaction increases because particles are closer together and so the frequency of collisions increases.
- BRate of reaction increases because there are more successful collisions.
- CRate of reaction increases because more of the particles have the required activation energy.
4Increasing the surface area of a solid reactant causes an increased rate of reaction. Why?
- AMore particles are exposed to the other reactant, meaning there are more collisions, so increasing the rate of reaction.
- BThe increased surface area means that the pressure of the reaction is increased, hence causing more collisions.
- CThe increased surface area increases the concentration of the reactant, resulting in more collisions.
5What do catalysts do?
- ASlow down the rate of reaction
- BIncrease the rate of reaction
- CActivate a reaction
6Why do catalysts not need replacing too often?
- AThey are not used up.
- BThey are unreactive.
7Which two statements best explain how catalysts speed up reactions?
A) Catalysts do not get used up during the reaction.
B) Catalysts make reactions exothermic.
C) Catalysts lower the activation energy of the reaction.
D) Catalysts provide a different route for a chemical reaction to occur.
E) Catalysts raise the temperature of the reaction.- AC and E
- BC and D
- CA and D
- DA and B
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- 11 practice questions
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