Question

The solubility of glucose at 30°C is 125 g/100 g water. Classify a solution made by adding 550 g of glucose to 400 mL of water at 30°C. Explain your classification, and describe how you could increase the amount of glucose in the solution without adding more glucose.

a) Saturated, because it contains the maximum amount of glucose at that temperature.
b) Unsaturated, because it contains less glucose than it could hold at that temperature.
c) Supersaturated, because it contains more glucose than it should at that temperature.
d) Saturated, because it contains equal amounts of glucose and water.

Answer 1

A solution made by adding 550 g of glucose to 400 mL of water at 30°C is classified as supersaturated because it contains more glucose than the solubility limit at that temperature. The temperature can be increased to dissolve more glucose without adding additional solute.

Step-by-step explanation:

The solubility of glucose at 30°C is 125 g/100 g water. When we have a solution where 550 g of glucose is added to 400 mL of water, we must first determine if this exceeds the solubility limit. Given that the density of water is approximately 1 g/mL, we can assume that 400 mL of water is roughly equal to 400 g of water. Therefore, the maximum amount of glucose that can be dissolved at 30°C in 400 g of water is 400 g × (125 g/100 g) = 500 g. Since 550 g of glucose is added, this exceeds the maximum solubility and, thus, the solution would be classified as supersaturated, because it contains more glucose than the maximum solubility at that temperature (c).

To increase the amount of glucose in the solution without adding more glucose, you could increase the temperature of the solution. As the temperature rises, the solubility of glucose in water generally increases, allowing more glucose to dissolve.