6.3 Catalysts
6 exam questions worth 10 marks. Write your answer, open the mark scheme, then give yourself the marks you earned. Your answers are saved on this device.
0 / 10
What is a catalyst?
Mark scheme
- substance that changes / increases the rate of a reaction (1)
- without being used up / chemically changed (1)
Model answer
A catalyst is a substance that increases the rate of a reaction without being used up.
Explain how a catalyst increases the rate of a reaction.
Mark scheme
- provides an alternative pathway with a lower activation energy (1)
- so more collisions are successful / have enough energy (1)
Model answer
It provides a different reaction pathway with a lower activation energy, so more collisions have enough energy to react.
Describe how a student could show that copper oxide is a catalyst for a reaction.
Mark scheme
- compare the rate with and without copper oxide (1)
- reaction faster with copper oxide (1)
- filter, dry and weigh copper oxide afterwards: mass unchanged (1)
Model answer
Do the reaction with and without copper oxide and compare the rates; it should be faster with the copper oxide. Then filter, dry and weigh the copper oxide to show its mass has not changed.
Why are catalysts not included in the balanced equation for a reaction?
Mark scheme
they are not used up / not reactants / unchanged at the end
Model answer
Because they are not used up in the reaction.
Give one reason why catalysts are useful in industry.
Mark scheme
faster reactions / lower temperatures needed / save energy / save money / reusable
Model answer
They allow reactions to happen quickly at lower temperatures, which saves energy and money.
Which statement about a reaction profile with a catalyst is correct?
Choose one answer.
Correct Not quite: the answer is The activation energy is lower but the overall energy change is the same
Mark scheme
B
Model answer
B: the activation energy is lower but the overall energy change is the same.
Found a mistake?