### GCSE Chemistry

Quantitative Chemistry
Chemical Changes
Energy Changes
Organic Chemistry
Chemical Analysis
Earth and Atmospheric Science
Using Resources

# Titration Calculations

Once a titration is completed, you can use the results to calculate the unknown variable using the following equation:

• Concentration is measured in mol/dm³
• Volume is measured in dm³
• The amount of solute is measured in mol

By plugging in the values obtained from your titration experiment into the equation, you can determine the concentration of a solution or the volume of solution required.

## Example

In a titration, a 25.0 cm³ solution of hydrochloric acid was required to neutralise 20.0 cm³ of 0.100 mol/dm³ sodium hydroxide solution. Calculate the concentration of the hydrochloric acid in mol/dm³ and g/dm³.

1. Write out the balanced equation

NaOH (aq) + HCl (aq) → NaCl (aq) + H2O (l)

2. Calculate the number of moles of sodium hydroxide (NaOH)

We can calculate the number of moles of NaOH using the formula:

Number of moles = (volume ÷ 1000) × concentration

Number of moles of NaOH = (20.0 ÷ 1000) × 0.100 = 0.0020 mol

3. Calculate the number of moles of hydrochloric acid (HCl)

As the mole ratio of NaOH : HCl is 1 : 1, the number of moles of HCl is also 0.0020 mol

4. Calculate the concentration of HCl in mol/dm³

We can calculate the concentration of HCl using the formula:

Concentration = number of moles / volume of solution

Concentration of HCl = 0.0020 / (25.0 ÷ 1000) = 0.080 mol/dm³

5. Calculate the concentration of HCl in g/dm³

The concentration of HCl can also be expressed in g/dm³ using the formula:

Mass = Relative formula mass × Number of moles

Relative formula mass of HCl = 35.5 + 1 = 36.5

Mass of HCl = 36.5 × 0.0020 = 0.073 g

Concentration of HCl = 0.073 g / (25.0 ÷ 1000) = 2.92 g/dm³

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