An industrial chemist wants to determine the percentage by mass of anhydrous ethanedioic acid (H2C2O4\text{H}_2\text{C}_2\text{O}_4H2C2O4) in a commercial brand of solid rust-remover.
She uses the following method:
The table below shows her experimental results:
| Measurement | Value |
|---|---|
| Mass of rust-remover sample | 0.450 g0.450\text{ g}0.450 g |
| Concentration of NaOH\text{NaOH}NaOH solution | 0.125 mol/dm30.125\text{ mol/dm}^30.125 mol/dm3 |
| Volume of NaOH\text{NaOH}NaOH solution added | 24.80 cm324.80\text{ cm}^324.80 cm3 |
Calculate the amount, in moles, of NaOH\text{NaOH}NaOH in 24.80 cm324.80\text{ cm}^324.80 cm3 of 0.125 mol/dm30.125\text{ mol/dm}^30.125 mol/dm3 sodium hydroxide solution.
In the titration, 2 mol2\text{ mol}2 mol of NaOH\text{NaOH}NaOH reacts with 1 mol1\text{ mol}1 mol of H2C2O4\text{H}_2\text{C}_2\text{O}_4H2C2O4. Calculate the amount, in moles, of H2C2O4\text{H}_2\text{C}_2\text{O}_4H2C2O4 in the rust-remover sample.
Calculate the mass, in grams, of H2C2O4\text{H}_2\text{C}_2\text{O}_4H2C2O4 in the rust-remover sample. [Mr of H2C2O4=90.0M_{\text{r}}\text{ of H}_2\text{C}_2\text{O}_4 = 90.0Mr of H2C2O4=90.0]
Calculate the percentage by mass of H2C2O4\text{H}_2\text{C}_2\text{O}_4H2C2O4 in the rust-remover sample.
39 exam-style questions on Edexcel IGCSE Chemistry Acids, alkalis and titrations. Each one has a worked solution and a mark scheme showing where the marks go.