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CAIE IGCSE Chemistry 3.2.3 Reacting masses in simple proportions

CAIE IGCSE Chemistry 3.2.3 Reacting masses in simple proportions
Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise using balanced equations and simple mass ratios to predict product or reactant masses without using the mole concept.

How this is tested

  • use formula masses and equation ratios to calculate masses in carbonate decompositions
  • find a product mass from a given reactant mass in reactions
  • account for incomplete decomposition when calculating the final mass left in a test-tube

Question 9

[Maximum number: 1]

The equation for the reaction between hydrogen sulfide, H2 S\mathrm{H}_{2} \mathrm{~S}, and oxygen is shown.

2H2 S+3O2→2SO2+2H2O2 \mathrm{H}_{2} \mathrm{~S}+3 \mathrm{O}_{2} \rightarrow 2 \mathrm{SO}_{2}+2 \mathrm{H}_{2} \mathrm{O}

Which mass of oxygen is required to react with 5.1 g of hydrogen sulfide?

A

2.4 g2.4 \mathrm{~g}

B

4.8 g4.8 \mathrm{~g}

C

7.2 g7.2 \mathrm{~g}

D

14.4 g14.4 \mathrm{~g}