CAIE IGCSE Chemistry Catalysts and Reaction Rate

Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise defining a catalyst as a substance that increases reaction rate while remaining chemically unchanged and distinguishing rate from final yield.

How this is tested

define a catalyst as increasing reaction rate while remaining chemically unchanged at the end
state that a catalyst changes how quickly products form but not the final stoichiometric amount
recognise that a catalyst can permit a lower operating temperature or pressure for a useful rate

[Maximum number: 1]

The equation for the decomposition of hydrogen peroxide, $\mathrm{H}_{2} \mathrm{O}_{2}$ , is shown.

2 \mathrm{H}_{2} \mathrm{O}_{2} \rightarrow 2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}

In an experiment, the total volume of oxygen produced is $100 \mathrm{~cm}^{3}$ .
The experiment is repeated using 1.00 g of a solid catalyst. All other conditions remain the same.
Which row describes the total volume of oxygen and the mass of the catalyst at the end of the second experiment?

total volume of oxygen
$/ \mathrm{cm}^{3}$

mass of catalyst
/g

more than 100

less than 1.00

100

less than 1.00

100

1.00

more than 100

1.00

How this is tested

Question 17