1.1. This is a method used to measure the solubility of a solid in water:

• add an excess of solid to some water in a boiling tube and stir

• measure the temperature of the saturated solution formed

• weigh an empty evaporating basin

• pour some of the saturated solution into the evaporating basin

• weigh the basin and contents

• heat the evaporating basin to remove all of the water

• weigh the evaporating basin and remaining solid

The table shows the results of an experiment using this method.

Calculate the mass of solid obtained and the mass of water removed.

mass of solid = .............................................................. g mass of water = .............................................................. g

1.2. In another experiment, at a different temperature, the mass of solid obtained is 10.5 g and the mass of water removed is 16.8 g.

Calculate the solubility of the solid, in g per 100 g of water, at this temperature.

solubility = .............................................................. g per 100 g of water

1.3. If the evaporating basin is heated too strongly, some of the solid decomposes to form a gas.

Explain how this strong heating would affect the value of the calculated solubility of the solid.