A KCl solution containing 38 g of KCl per 100.0 g of water is cooled from 60 °C to 0 °C. What happens during cooling? (Use Figure 14.11.)

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Identify the solubility of KCl at 60 °C using Figure 14.11. This will tell you how much KCl can dissolve in 100 g of water at this temperature.

Determine the solubility of KCl at 0 °C using the same figure. This will indicate how much KCl can remain dissolved in 100 g of water at the lower temperature.

Compare the initial concentration of KCl (38 g per 100 g of water) with the solubility at 0 °C. This will help you understand if the solution is supersaturated, saturated, or unsaturated at 0 °C.

If the initial concentration is higher than the solubility at 0 °C, calculate the amount of KCl that will precipitate out of the solution as it cools.

Describe the physical changes that occur during the cooling process, such as the formation of KCl crystals if the solution becomes supersaturated.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Solubility

Solubility refers to the maximum amount of a solute that can dissolve in a solvent at a given temperature and pressure. In the case of KCl in water, solubility decreases as temperature decreases, meaning that less KCl can remain dissolved in the solution when cooled from 60 °C to 0 °C.

Crystallization

Crystallization is the process where dissolved solute particles come together to form solid crystals as the solution becomes supersaturated. As the KCl solution cools, it may reach a point where the concentration of KCl exceeds its solubility limit, leading to the formation of KCl crystals.

Phase Changes

Phase changes involve transitions between solid, liquid, and gas states of matter. In this scenario, as the KCl solution cools, the temperature drop can lead to a phase change where dissolved KCl transitions from the aqueous phase to the solid phase, resulting in the precipitation of KCl crystals.

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A KNO3 solution containing 35 g of KNO3 per 100.0 g of water is cooled from 40°C to 0°C. What happens during cooling? (Use Figure 14.11.)

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A KNO3 solution containing 35 g of KNO3 per 100.0 g of water is cooled from 40 °C to 0 °C. What happens during cooling? (Use Figure 14.11.)

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