What are catalysts?
3 marks · NormalExplain, with reasons, how you could show experimentally that manganese(IV) oxide is not chemically changed during the decomposition of hydrogen peroxide.
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.
Show answer
Must show: Weigh MnO2 before reaction, Filter and dry after reaction, Weigh residue; mass is unchanged
Also accept: Alternative mention of chemical tests showing substance is MnO2
Common mistakes: Stating only observe appearance; Forgetting to filter or dry
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Weighs the manganese(IV) oxide before the reaction.
M2 · 1 mark · Filters off and dries the manganese(IV) oxide after the reaction.
A1 · 1 mark · Shows the mass (or description/chemical composition) has not changed, so it is chemically unchanged.
Worked solution
First, weigh the manganese(IV) oxide before adding it to the hydrogen peroxide. After the reaction, filter out the solid using filter paper, and allow it to dry. Weigh the dried manganese(IV) oxide and compare the mass before and after. If the mass is the same, this shows that it has not been chemically changed during the reaction.