Determine the mass of the solution with a mass fraction of 5% sodium hydroxide required for interaction

| September 10, 2021 | education

Determine the mass of the solution with a mass fraction of 5% sodium hydroxide required for interaction with 150 g of a 15% solution of copper sulfate 2.

Find the mass of copper sulfate in solution.

The mass fraction of a substance is calculated by the formula:

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

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

m (substance) = (150 g × 15%): 100% = 22.5 g.

Let’s find the amount of copper sulfate substance by the formula:

n = m: M.

M (CuSO4) = 64 + 32 + 64 = 160 g / mol.

n = 22.5 g: 160 g / mol = 0.14 mol.

Let’s compose the reaction equation, find in what quantitative ratios the substances are.
CuSO4 + 2NaOH = Na2SO4 + Cu (OH) 2 ↓.

For 2 mol of sodium hydroxide there is 1 mol of copper sulfate. Substances are in quantitative ratios of 2: 1.

The amount of sodium hydroxide substance will be 2 times more than copper sulfate.

n (NaOH) = 2n (CuSO4) = 2 × 0.14 = 0.28 mol.

Find the mass of potassium carbonate.

m = n × M,

M (NaOH) = 40 g / mol.

m = 0.28 mol × 40 g / mol = 11.2 g.

The mass fraction of a substance is calculated by the formula:

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

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

m (solution) = (11.2 g: 5%) × 100% = 224 g.

Answer: 224 g.



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