Calculate the mass of the precipitate obtained by the interaction of a magnesium sulfate solution

| June 10, 2021 | education

Calculate the mass of the precipitate obtained by the interaction of a magnesium sulfate solution with a potassium hydroxide solution weighing 450 g with a mass fraction of KOH of 20%

1. Let’s find the mass of KOH in solution, using the formula:

m (KOH) = m (solution) * w (solution) / 100% = 450 * 20/100 = 90 g

2. Let’s compose the reaction equation:

MgSO4 + 2 KOH = Mg (OH) 2 + K2SO4

According to the equation:

2 mol of KOH enters the reaction;
1 mol of Mg (OH) 2 precipitate is formed
Let’s find the mass of KOH by the formula:

m (KOH) = n * M = 2 mol * (39 + 16 + 1) = 112 g

Let’s find the mass of Mg (OH) 2 by the formula:

m (Mg (OH) 2) = n * M = 1 mol * (24 + (16 + 1) * 2) = 58 g

3. Let’s calculate the mass of the sediment, making up the proportion:

90 g KOH – x g Mg (OH) 2

112 g KOH – 58 g Mg (OH) 2

Hence, x = 90 * 58/112 = 46.6 g.



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