36.6k views
0 votes
!!!50 points!!!

Problem 1. What masses of 15% and 20% solutions are needed to prepare 200 g of 17% solution?
Problem 2. What masses of 18% and 5% solutions are needed to prepare 300 g of 7% solution?
Problem 3. 200 g of 15% and 350 g of 20% solutions were mixed. Calculate mass percentage of final solution.
Problem 4. 300 g of 15% solution and 35 g of solute were mixed. Calculate mass percentage of final solution.
Problem 5. 400 g of 25% solution and 150 g of water were mixed. Calculate mass percentage of final solution.

1 Answer

4 votes

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%.

User Joviallix
by
8.2k points

No related questions found