C = Moles part 1

Question 1

Moles = ? (Solids)

Units?

Answer 1

Moles = Mass / Molar mass

Moles = mol
Mass = g
Molar mass(Mr) = g/mol

Question 2

Describe an experiment where you have to analyse Epsom salts

Answer 2

• MAKING HYDRATED MAGNESIUM SULPHATE CRYSTALS (Epsom salts)

1-Measure out specified volume of your H2SO4 and mass of magnesium carbonate

2-Add the spatulas of magnesium carbonate into the acid. Use a glass rod to stir the mixture until all visible signs of reaction have stopped. Do this is a beaker

3-Filter the solution using filter paper. Catch the filtrate into an evaporating basin

4-Heat the filtrate (not until it becomes dry but until its volume has reduced to about one third of its original volume

5-Leave for liquid to evaporate and crystalize

Question 3

Steps of the mole calculations?

Answer 3

1-Balanced symbol equation

2-Reacting ratios

3-Use imformation given to you from the question to work out the moles of one of the reactants/products

4-Molar ratio

5-Moles = mass / molar mass
Work out the unknown

Question 4

How to calculate empirical formulae?

Answer 4

1 - Use mass or % data

2 - Divide the mass/% data by the Mr of the element e.g. 12g of Sodium would mean you would so 12 / 23 = 0.56

3 - Divide the answers you get by the smallest answer

4 - Scale up or down accordingly to find the simplest WHOLE ratio

Question 5

Define empirical formulae

Answer 5

Simplest fixed ratio of atoms present in a compound

Question 6

Define molecular formulae

Answer 6

The actual formula of a compound e.g. the fixed ratio of atoms present in a compound