Skip to content

Course home

Question bank·2.6 Calculations involving masses

2.6 Calculations involving masses

Easy Medium Hard

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

Question 3

Washing soda crystals are hydrated sodium carbonate. A 5.72 g sample of the crystals is heated until its mass stops changing, which leaves 2.12 g of anhydrous sodium carbonate, $Na2CO3\mathrm{Na_{2}CO_{3}}$ .

Relative formula masses: $Na2CO3=106\mathrm{Na_{2}CO_{3}} = 106$ , $H2O=18\mathrm{H_{2}O} = 18$ .

Which formula represents washing soda crystals?

[1]

A

$Na2CO3⋅16H2O\mathrm{Na_{2}CO_{3}\cdot 16H_{2}O}$

B

$Na2CO3⋅2H2O\mathrm{Na_{2}CO_{3}\cdot 2H_{2}O}$

C

$Na2CO3⋅11H2O\mathrm{Na_{2}CO_{3}\cdot 11H_{2}O}$

D

$Na2CO3⋅10H2O\mathrm{Na_{2}CO_{3}\cdot 10H_{2}O}$

Markscheme

2.6 Calculations involving masses Questions

GCSE
Chemistry
2.6 Calculations involving masses

142 exam-style questions on Edexcel GCSE Chemistry 2.6 Calculations involving masses, covering 2.6.1 Relative formula mass and percentage composition, 2.6.2 Empirical and molecular formulae, 2.6.3 Conservation of mass, 2.6.4 Reacting masses and concentration in g dm⁻³, 2.6.5 The mole and the Avogadro constant, and 2.6.6 Limiting reactants and stoichiometry. Each one has a worked solution and a mark scheme showing where the marks go.

More questions