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CAIE A-Level Chemistry AS 2.2 The Mole and the Avogadro Constant Questions

Practise converting among amount, mass and particle number while counting atoms, ions or molecules at the correct level.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • convert mass to amount using molar mass before multiplying by the Avogadro constant
  • count atoms, ions or molecules by applying formula subscripts to the amount of substance
  • use mole ratios in formula or hydrate calculations to identify n or a relative formula mass

Covered syllabus points

2.2.1—Terms: mole

Question 1

[Maximum number: 1]

Which of these samples of gas contains the same number of atoms as 1 g of hydrogen gas?

A

22 g of carbon dioxide ( Mr:CO2,44M_{\mathrm{r}}: \mathrm{CO}_{2}, 44 )

B

8 g of methane (Mr:CH4,16)\left(M_{\mathrm{r}}: \mathrm{CH}_{4}, 16\right)

C

20 g of neon ( Mr:Ne,20M_{\mathrm{r}}: \mathrm{Ne}, 20 )

D

8 g of ozone ( Mr:O3,48M_{\mathrm{r}}: \mathrm{O}_{3}, 48 )

Question 2

[Maximum number: 1]

How many molecules are present in 62 g of solid white phosphorus, P4\mathrm{P}_{4} ?

A

L

B

2 L

C

L2\frac{L}{2}

D

L4\frac{L}{4}

Question 3

[Maximum number: 1]

Molten aluminium chloride has a simple molecular structure. Each molecule consists of two aluminium atoms and six chlorine atoms.

Which statement is correct?

A

All the chlorine atoms in 1 g of molten aluminium chloride have the same mass.

B

One mole of molten aluminium chloride contains 6.02×10236.02 \times 10^{23} aluminium atoms.

C

One mole of molten aluminium chloride contains 3.61×10243.61 \times 10^{24} chlorine atoms.

D

The empirical formula of molten aluminium chloride is Al2Cl6\mathrm{Al}_{2} \mathrm{Cl} 6.

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