Answer:
See Below.
Step-by-step explanation:
Problem 1
Let x be the mass of 15% solution needed and y be the mass of 20% solution needed. Then, we have the following system of equations:
x + y = 200 (total mass of solution)
0.15x + 0.20y = 0.17(200) (total amount of solute)
Solving this system of equations gives:
x = 60 g (mass of 15% solution)
y = 140 g (mass of 20% solution)
Therefore, 60 g of 15% solution and 140 g of 20% solution are needed to prepare 200 g of 17% solution.
Problem 2
Let x be the mass of 18% solution needed and y be the mass of 5% solution needed. Then, we have the following system of equations:
x + y = 300 (total mass of solution)
0.18x + 0.05y = 0.07(300) (total amount of solute)
Solving this system of equations gives:
x = 120 g (mass of 18% solution)
y = 180 g (mass of 5% solution)
Therefore, 120 g of 18% solution and 180 g of 5% solution are needed to prepare 300 g of 7% solution.
Problem 3
The total mass of the final solution is
200 g + 350 g = 550 g
The total amount of solute in the final solution is:
0.15(200 g) + 0.20(350 g) = 95 g + 70 g = 165 g
Therefore, the mass percentage of the final solution is:
(mass of solute / total mass of solution) x 100% = (165 g / 550 g) x 100% = 30%
Therefore, the mass percentage of the final solution is 30%.
Problem 4
The total mass of the final solution is
300 g + 35 g = 335 g
The total amount of solute in the final solution is:
0.15(300 g) + 35 g = 75 g + 35 g = 110 g
Therefore, the mass percentage of the final solution is:
(mass of solute / total mass of solution) x 100% = (110 g / 335 g) x 100% = 32.8%
Therefore, the mass percentage of the final solution is 32.8%.
Problem 5
The total mass of the final solution is
400 g + 150 g = 550 g
The total amount of solute in the final solution is
0.25(400 g) = 100 g
Therefore, the mass percentage of the final solution is
(mass of solute / total mass of solution) x 100% = (100 g / 550 g) x 100% = 18.2%
Therefore, the mass percentage of the final solution is 18.2%.