Calculations

Question 1

% mass of an element

Answer 1

% mass of an element = (Ar x number of atoms of that element) ÷ (Mr of component) x 100

Question 2

Number of moles

Answer 2

Number of moles = mass ÷ Mr

OR

Number of moles = concentration x volume

Question 3

Volume of gas

Answer 3

Volume of gas = (mass of gas) ÷ (Mr of gas) x 24

Question 4

Concentration

Answer 4

Concentration = mass ÷ volume

OR

Concentration = number of moles ÷ volume