A student investigated the change in mass when hydrated copper sulfate was heated.
The word equation for the reaction is:
hydrated copper sulfate⇌anhydrous copper sulfate+water \text{hydrated copper sulfate} \rightleftharpoons \text{anhydrous copper sulfate} + \text{water} hydrated copper sulfate⇌anhydrous copper sulfate+waterThis is the method used:
The table below shows the results.
| Total heating time in seconds | Mass of boiling tube and contents in grams |
|---|---|
| 0 | 31.8 |
| 30 | 31.1 |
| 60 | 30.6 |
| 90 | 30.6 |
Determine the mass of the empty boiling tube.
Explain why the mass of the boiling tube and contents decreased.
Suggest why the boiling tube and contents were heated until the mass did not change.
When 250 g250\text{ g}250 g of hydrated copper sulfate is heated until the mass does not change, 78.2 kJ78.2\text{ kJ}78.2 kJ of energy is taken in. The student heated 3.50 g3.50\text{ g}3.50 g of hydrated copper sulfate until the mass did not change. Calculate the energy taken in during this reaction. Give your answer to 3 significant figures.
What type of reaction takes place when hydrated copper sulfate is heated?
53 exam-style questions on AQA GCSE Chemistry 3.1 Chemical measurements, conservation of mass and the quantitative interpretation of chemical equations, covering 3.1.1 Conservation of mass and balanced chemical equations, 3.1.2 Relative formula mass, 3.1.3 Mass changes when a reactant or product is a gas, and 3.1.4 Chemical measurements. Each one has a worked solution and a mark scheme showing where the marks go.