Relative Masses of Atoms & Molecules (Cambridge O Level Chemistry)

Topic Questions

11 mark

Leucine is an essential amino acid used in the synthesis of proteins in the body.

BuC2vATv_q4-2-4-mcq-easy-cie-igcse-cheWhat is the relative molecular mass of leucine?

  • 144 g

  • 86 g

  • 125 g

  • 131 g

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1 mark

What mass of magnesium oxide is formed when 21 g of magnesium carbonate thermally decomposes via the following equation. (Ar = Mg = 24, C = 12, O = 16)

MgCO3 (s) → MgO (s) + CO2 (g) 

  • 10

  • 11

  • 20

  • 22

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11 mark

Ammonia is manufactured by the reaction of hydrogen and nitrogen in the Haber process, as shown in the equation below:

N2 + 3 H2 → 2 NH3

16.8 tonnes of ammonia can be produced from 14 tonnes of nitrogen.

How much nitrogen is needed to produce 51 tonnes of ammonia?

  • 42.5

  • 34

  • 17

  • 24.5

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11 mark

6 g of hydrogen react with 48 g of oxygen to form water. A chemist performs the same reaction using 2 g of hydrogen.

What mass of oxygen is required to combine with the hydrogen?

  • 24 g

  • 12 g

  • 16 g

  • 72 g

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