How many grams of copper sulfate must be mixed with 450 g of water to obtain a solution with a mass fraction of 10%.

Given:

m (water) = 450 g,

w = 10%,

m (substances) -?

Decision :

w = m (substance): m (solution) × 100%, hence

m (substance) = (m (solution) × W): 100%.

m (solution) = m (water) + m (substance).

Let m g CuSO4 be added to 450 g water to obtain a 10% solution.

m (solution) = 450 g + m.

10% = m: (450 g + m) × 100%,

4500 + 10 m = 100 m,

4500 = 100 m – 10 m,

4500 = 90 m

m = 4500: 90,

m = 50.

Answer: You need to add 50 g of CuSO4.