Catalysts in industry
3 marks · NormalYou are given an unknown white powder and asked to find out if it is a catalyst for the decomposition of hydrogen peroxide solution. Describe how you would show that this substance is a catalyst in the reaction.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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Must show: Step to show faster reaction, Step to recover and check catalyst after reaction
Also accept: Add the powder to hydrogen peroxide, observe rate increase compared to control, recover powder after reaction and compare if unchanged
Common mistakes: Only showing faster rate, not that catalyst is unchanged; Claiming catalyst is used up
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Describes adding the powder to hydrogen peroxide and comparing rate to a control (no powder).
E1 · 1 mark · Observes the reaction is faster (more gas produced, faster bubbling, or time measured).
C1 · 1 mark · States the powder should be unchanged after the reaction (can be filtered, dried and weighed/compared).
Worked solution
To show the powder is a catalyst: 1. Add some of the powder to hydrogen peroxide solution and measure the rate at which oxygen is produced (e.g., using a gas syringe or by timing the effervescence). Set up a control with no powder for comparison. (M1) 2. If the reaction is faster with the powder present, this shows it increases the rate. (E1) 3. Filter and recover the powder after the reaction, dry it, and compare it to the original powder. If it is unchanged, it is a catalyst. (C1)