Question

The solubility of a substance is 12g per 100g of water at 20°c. it is 18g per 100g of water at 60°c. how many grams of substance can crystallize from a saturated solution that contains 200g of water at 60°c if the solution is cooled to 20°c?

Answer 1

When the 200g water at 60°C is cooled to 20°C, 12g of the substance will crystallize out of the solution.

Step-by-step explanation:

To determine how many grams of substance can crystallize from a saturated solution that contains 200g of water at 60°C when the solution is cooled to 20°C, we need to compare the solubility at 60°C to the solubility at 20°C. The solubility of the substance at 60°C is 18g per 100g of water, while at 20°C it is 12g per 100g of water.

This means that at 60°C, 200g of water can dissolve 36g of the substance (18g per 100g × 200g/100g). However, at 20°C, 200g of water can only dissolve 24g of the substance (12g per 100g × 200g/100g).

Since the solution starts with 200g of water at 60°C, it is already saturated and contains 36g of the substance. When the solution is cooled to 20°C, it can only dissolve 24g of the substance. This means that 12g of the substance (36g - 24g) will crystallize out of the solution.