The solubility of copper (II) tetraoxosulphate (Iv) is 75g in 100g of water at 100°C and 25g in 100g of water at 30°C. What mass of the salt would crystalli...

Answer Details

The solubility of copper (II) tetraoxosulphate (IV) is given as 75g in 100g of water at 100°C and 25g in 100g of water at 30°C. This means that at 100°C, 100g of water can dissolve up to 75g of the salt while at 30°C, 100g of water can dissolve up to 25g of the salt. If 50g of copper (II) tetraoxosulphate (VI) solution saturated at 100°C were cooled to 30°C, some of the salt would crystallize out since the solubility of the salt in water decreases as the temperature decreases. First, we need to find out how much of the salt is already dissolved in the 50g solution. At 100°C, 100g of water can dissolve 75g of the salt. Therefore, in 50g of water, we can dissolve: (75g/100g) x 50g = 37.5g of copper (II) tetraoxosulphate (IV) This means that 37.5g of the salt is already dissolved in the 50g solution at 100°C. When the solution is cooled to 30°C, the solubility of the salt reduces to 25g/100g of water. This means that the maximum amount of salt that can be dissolved in 50g of water at 30°C is: (25g/100g) x 50g = 12.5g of copper (II) tetraoxosulphate (IV) Therefore, the amount of salt that would crystallize out is the difference between the amount of salt already dissolved in the solution and the maximum amount of salt that can be dissolved in the solution at 30°C: 37.5g - 12.5g = 25g So, 25g of copper (II) tetraoxosulphate (IV) would crystallize out when 50g of the saturated solution at 100°C is cooled to 30°C. Therefore, the answer is 14.3g.