1. Relative Formula Mass
This is the total mass of the sum of all the relative atomic masses of the elements in a compound.

2. What will you need to do?
Calculate the relative formula mass of compounds whose formulae are supplied.
Calculate the percentages of elements in compounds whose formulae are supplied.

3. Calculate the Relative Formula Mass of compounds whose formulae are supplied.
Carbon Dioxide
Carbon C = 12 Oxygen O = 16
Carbon Dioxide CO2 = *16 = 44
Relative formula mass of Carbon Dioxide = 44

4. Here are some examples….2
H2O 18
FeO 72
100
CaCO3

5. Calculate the percentages of elements in compounds whose formulae are supplied.
Water
Oxygen 1*16 = 16
Hydrogen 2*1 = 2
Relative formula mass H2O = 2*1+16 = 18
% Hydrogen = 2/18*100 = 11%
% Oxygen = 16/18*100 = 89%

6. Here are some examples…
CO2
H2SO4
CuSO4
NaCl