A)250 g of LiBr is dissolved in 200g of water 100 degrees C. The solution is then cooled to 20 degrees C. How much precipitate (if any) is formed?

B) 42 g of KCl is dissolved in 100g of water at 50 degrees C. The solution is then cooled to 20 degrees C. How much precipitate (if any) is formed?

You must have a chart showing the solubility of LiBr and KCl. I don't have that chart. I don't know how I can help.

To determine if a precipitate will be formed in a solution, we need to compare the solubility of the solute at different temperatures. The solubility of a substance refers to the maximum amount of solute that can dissolve in a given amount of solvent at a specific temperature.

In this case, we need to compare the solubility of LiBr and KCl at 20 degrees C to determine if a precipitate will form.

A) LiBr:
1. Find the solubility of LiBr at 100 degrees C: You can search for a solubility table or use a reliable source to find the solubility of LiBr at 100 degrees C. Let's assume it is fully soluble.
2. Calculate the solubility of LiBr at 20 degrees C: Since the solution is cooled from 100 degrees C to 20 degrees C, the solubility may change. You can search for a solubility table or use a reliable source to find the solubility of LiBr at 20 degrees C. Let's assume it is soluble up to 100 g per 100 g of water.
3. Calculate the amount of LiBr dissolved at 100 degrees C: 250 g of LiBr is fully dissolved in the water at 100 degrees C.
4. Compare the amount of LiBr dissolved at 100 degrees C to the solubility at 20 degrees C: Since the amount of LiBr dissolved at 100 degrees C is greater than the solubility at 20 degrees C, a precipitate will form.

B) KCl:
1. Find the solubility of KCl at 50 degrees C: You can search for a solubility table or use a reliable source to find the solubility of KCl at 50 degrees C. Let's assume it is soluble up to 40 g per 100 g of water.
2. Calculate the solubility of KCl at 20 degrees C: Since the solution is cooled from 50 degrees C to 20 degrees C, the solubility may change. You can search for a solubility table or use a reliable source to find the solubility of KCl at 20 degrees C. Let's assume it is soluble up to 30 g per 100 g of water.
3. Calculate the amount of KCl dissolved at 50 degrees C: 42 g of KCl is fully dissolved in the water at 50 degrees C.
4. Compare the amount of KCl dissolved at 50 degrees C to the solubility at 20 degrees C: Since the amount of KCl dissolved at 50 degrees C is greater than the solubility at 20 degrees C, a precipitate will not form.

To summarize:
A) A precipitate will form when cooling the LiBr solution from 100 degrees C to 20 degrees C.
B) No precipitate will form when cooling the KCl solution from 50 degrees C to 20 degrees C.