How much

• usually the same number as the mass number
• the relative atomic masses added together
• eg: mgcl2 = 24 + (35.5 x 2) = 95

1. Change the % given to the masses of each element in 100g compound

2. Change masses to moles (divide by Ar values)

3. This tells you the ratio

4. The simplest whole number ratio gives you the formula

• yeild is the amount of product a chemical reaction makes
• percentage yeild is what we really get compared to what we might get

Percentage yeild = amount of product produced divided by maximum amount of produced product X 100

• reactions may be reversible
• some products might be lost in handling or left behind in equipment
• some chemical reactions may produce more than one product

• a reversible reaction is when the products of a reaction can be reacted to produce the original reactants