The mole unit

Avogadros number

6.02²³ x 10 particles

Volume ratio

1mL ÷ 1cm³

Density

g ÷ 1cm³

Molar mass

g/mol

Percentage composition

% of element = (mass of element in compound ÷ molar mass of compound) × 100

Empirical formula

1. Assume 100 g sample

2. Convert % → grams

3. Convert grams → moles

4. Divide all moles by the smallest value

5. Multiply to get whole numbers if needed

6. Then add it as a subscript to the elements

Molecular formula

• Find empirical formula

• Calculate empirical formula mass

• Divide molecular molar mass ÷ empirical formula mass

• Multiply subscripts by this whole number

Limiting reactant

• Convert both reactants to moles

• Multiply initial # of mol by the mole ratio of product ÷ reactant

• The reactant that produces less product is the limiting reactant

Percentage composition

% Yield = (Experimental ÷ Theoretical) × 100