Question 3
FHydrogen peroxide solution slowly decomposes to make water and oxygen.
2H2O2→2H2O+O2 2\mathrm{H_{2}O_{2}} \rightarrow 2\mathrm{H_{2}O} + \mathrm{O_{2}} 2H2O2→2H2O+O2Manganese(IV) oxide is a catalyst for this reaction.
a.[2]
Which two statements about catalysts are correct?
Statement 1: A catalyst speeds up a reaction.
Statement 2: A catalyst is used up in the reaction.
Statement 3: A catalyst is not chemically changed at the end of the reaction.
Statement 4: A catalyst increases the mass of product made.
Statement 5: A catalyst increases the activation energy.
Write the numbers of the two correct statements.
b.[1]
A student adds 0.50 g of manganese(IV) oxide to some hydrogen peroxide solution. When the reaction stops, the student filters off the manganese(IV) oxide, dries it and weighs it. Its mass is 0.50 g.
What does this result show about the manganese(IV) oxide?
c.i.[1]
The diagram shows the reaction profiles for the decomposition of hydrogen peroxide with and without a catalyst.
Which arrow, A, B or C, shows the activation energy with a catalyst?
c.ii.[2]
Explain how a catalyst increases the rate of a reaction. Use the diagram.
d.[1]
Liver contains catalase. Catalase is an enzyme that speeds up the decomposition of hydrogen peroxide.
What is an enzyme?
e.[2]
Margarine is made by reacting vegetable oil with hydrogen gas at 60 °C.
At the start, the reaction vessel contains vegetable oil, hydrogen and nickel.
At the end, the reaction vessel contains margarine and nickel.
Identify the catalyst in this reaction. Give a reason for your answer.
5.2 Controlling reactions Questions
56 exam-style questions on OCR GCSE Chemistry 5.2 Controlling reactions, covering 5.2.1 Measuring and interpreting rate of reaction, 5.2.2 Factors affecting rate and collision theory, and 5.2.3 Catalysts, activation energy and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.