The solubility of a substance is 12.0 g per 100.0 g of water at 60 C. How many grams of the substance can crystallize from a saturated solution that contains 200.0 g of water at 60 C if the solution is cooled to 20 C?
Don't I need to know the solubility at 20 C?
12 g
To solve this problem, we need to understand that solubility is affected by temperature. As the solution cools, its solubility decreases, leading to the precipitation of the solute.
Given:
- Solubility of the substance at 60°C is 12.0 g per 100.0 g of water.
- Amount of water in the solution is 200.0 g.
- The solution is cooled to 20°C.
To find the amount of solute that can crystallize from the solution, we need to determine the saturated mass of the solute at 20°C.
Step 1: Calculate the maximum solubility of the substance at 20°C.
Since the solubility is given at 60°C, we need to determine the solubility at 20°C. To do this, we use the solubility curve or table for the substance. Let's assume the solubility at 20°C is 8.0 g per 100.0 g of water.
Step 2: Calculate the saturated mass of solute at 20°C.
To determine the amount of solute that can crystallize from 200.0 g of water at 20°C, we need to consider the solubility limit. At 20°C, the maximum solubility is 8.0 g per 100.0 g of water. Therefore, for 200.0 g of water, the saturated mass of solute can be calculated as follows:
Saturated mass = (Maximum solubility) x (Mass of water) / 100
= (8.0 g / 100.0 g) x (200.0 g)
= 16.0 g
Therefore, 16.0 grams of the substance can crystallize from the saturated solution containing 200.0 grams of water when cooled to 20°C.