A student is carrying out a gravimetric analysis to determine the mass of water of crystallisation in a sample of hydrated cobalt(II) chloride (CoCl2⋅6H2O{\text{CoCl}}_2 \cdot 6{\text{H}}_2{\text{O}}CoCl2⋅6H2O).
The student uses the following method:
Step 1 Record the mass of a clean, dry evaporating basin. Step 2 Add a sample of hydrated cobalt(II) chloride to the basin and record the combined mass. Step 3 Heat the basin and its contents strongly using a blue Bunsen burner flame to drive off the water. Step 4 Allow the basin and its contents to cool to room temperature. Step 5 Record the final mass of the basin and the anhydrous cobalt(II) chloride.
Explain how the student could ensure that all of the water of crystallisation has been completely removed from the sample.
258 exam-style questions on Edexcel GCSE Chemistry Calculations involving masses. Each one has a worked solution and a mark scheme showing where the marks go.