A saturated solution of barium chloride at 30 °C contains 150 g water. How much additional barium chloride can be dissolved by heating this solution to 80 °C?
2. A solution of KCl is saturated at 20 °C.
a) How many grams of solute are dissolved in 100 g of water?
b) What is the total mass of the solution?
c) What is the mass percent of this solution at 50 °C?
d) If the solution is heated to 50 °C, how much more KCl can be dissolved in the solution without adding more water?
e) If the solution is saturated at 100 °C and then cooled to 30 °C, how many grams of solute will precipitate out?
To find the answers to these questions, we need to understand the concept of solubility and how it changes with temperature. 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 order to get the answers, we can use the solubility data for the specific substances involved, which typically can be found in reference tables or online resources. Let's go through each question step by step.
Question 1:
A saturated solution of barium chloride at 30 °C contains 150 g water. How much additional barium chloride can be dissolved by heating this solution to 80 °C?
To find the amount of additional barium chloride that can be dissolved, we need to compare the solubility at 30 °C to the solubility at 80 °C.
1. Find the solubility of barium chloride at 30 °C. Let's assume it is X grams/100 grams of water (this is just a placeholder for the actual solubility value).
2. Find the solubility of barium chloride at 80 °C. Let's assume it is Y grams/100 grams of water.
3. Subtract the initial solubility (X grams/100 grams of water) from the final solubility (Y grams/100 grams of water).
4. Multiply the difference obtained in step 3 by 150 g (the initial amount of water) to get the additional amount of barium chloride that can dissolve in the heated solution.
Question 2:
A solution of KCl is saturated at 20 °C.
a) How many grams of solute are dissolved in 100 g of water?
To find the amount of solute dissolved in 100 g of water, we need to know the solubility of KCl at 20 °C.
1. Find the solubility of KCl at 20 °C. Let's assume it is Z grams/100 grams of water.
2. Multiply the solubility obtained in step 1 by 100/100 to find the amount of solute dissolved in 100 g of water.
b) What is the total mass of the solution?
The total mass of the solution is the sum of the mass of the water and the mass of the solute dissolved in it.
1. Add the mass of solute obtained in question 2a) to 100 g (mass of water) to get the total mass of the solution.
c) What is the mass percent of this solution at 50 °C?
To find the mass percent, we need the mass of the solute and the total mass of the solution at 50 °C.
1. Find the solubility of KCl at 50 °C. Let's assume it is A grams/100 grams of water.
2. Calculate the mass of solute dissolved in 100 g of water using the solubility obtained in step 1, as done in question 2a).
3. Multiply the mass of solute obtained in step 2 by the desired amount of water (let's assume it is B g). This gives the mass of solute in B g of water.
4. Add the mass of solute obtained in step 3 to B g (mass of water) to get the total mass of the solution.
5. Divide the mass of solute obtained in step 3 by the total mass of the solution calculated in step 4.
6. Multiply the result from step 5 by 100 to get the mass percent of the solution at 50 °C.
d) If the solution is heated to 50 °C, how much more KCl can be dissolved in the solution without adding more water?
To find the additional amount of KCl that can be dissolved, we compare the solubility at 20 °C to the solubility at 50 °C.
1. Find the solubility of KCl at 20 °C (Z grams/100 grams of water) and at 50 °C (A grams/100 grams of water).
2. Subtract the initial solubility (Z grams/100 grams of water) from the final solubility (A grams/100 grams of water).
3. Multiply the difference obtained in step 2 by the mass of water provided (100 g) to get the additional amount of KCl that can dissolve without adding more water.
e) If the solution is saturated at 100 °C and then cooled to 30 °C, how many grams of solute will precipitate out?
To find the amount of solute that will precipitate out upon cooling, we need to compare the solubility at 100 °C to the solubility at 30 °C.
1. Find the solubility of KCl at 100 °C. Let's assume it is C grams/100 grams of water.
2. Find the solubility of KCl at 30 °C. Let's assume it is D grams/100 grams of water.
3. Subtract the initial solubility (C grams/100 grams of water) from the final solubility (D grams/100 grams of water).
4. Multiply the difference obtained in step 3 by the mass of water provided (100 g) to get the amount of solute that will precipitate out upon cooling.