Mole calculations: 4.3.2 Use of amount of substance in relation to masses of pure substances: Chemistry AQA Q&A: GCSE (9:1)

moles

In chemistry, the amount of substance is measured in:

1 mole of calcium carbonate weighs 100 g

Calcium carbonate has a Mr of 100. This means that:

1.8 x 10²⁴

One mole of copper contains 6 x 10²³ atoms. How many atoms will three moles of calcium contain?

2

18 grams of water, H₂O, contains 1 mole of water molecules. How many moles of hydrogen atoms does this contain?

245 g

What is the mass of 2.5 moles of sulfuric acid, H₂SO₄?

106

Calculate the relative formula mass, Mr, of Na₂CO₃

0.25

Calculate the number of moles in 20 grams of ammonium nitrate, NH₄NO₃ (Mr = 80)

32 g

3. Sulphur burns in air to form sulphur dioxide:

S + O₂ → SO₂

Work out the mass of sulphur that must be burned to produce 64g of sulphur dioxide.

7.3 g

12.0g ethanol (C₂H₅OH) is reacted to produce ethene (C₂H₄).

C₂H₅OH → C₂H₄ + H₂O

Calculate the mass of ethene made and give your answer to 1 decimal place.

5.6 g

Calculate the mass of iron that can be made when 8 grams of iron (III) oxide is reduced in the following equation:

2Fe₂O₃ + 3C → 4Fe + 3CO₂

HCl

1 gram of calcium carbonate was reacted with 0.4 grams of HCl according to the equation below:

CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

Which is the limiting reagent?

Na₂CO₃

21.2 grams of sodium carbonate was reacted with 0.5 moles of nitric acid according to the equation below:

Na₂CO₃ + 2HNO₃ → 2NaNO₃ + H₂O + CO₂

Which is the limiting reagent?