Calculate the mass with a mass fraction of nitric acid of 12% required to dissolve 8g. magnesium oxide.

univerkov | January 31, 2021 | education

1.Let’s find the amount of magnesium oxide substance by the formula: n = m: M.

M (MgO) = 24 + 16 = 40 g / mol.

n = 8: 40 = 0.2 mol.

2.MgO + 2HNO3 = Mg (NO3) 2 + H2O.

For 1 mol of magnesium oxide, there are 2 mol of nitric acid. The substances are in quantitative ratios of 1: 2.

The amount of acid substance will be 2 times more than the amount of magnesium oxide substance.

n (HNO3) = 0.2 mol × 2 = 0.4 mol.

m = n × M,

M (HNO3) = 1 + 14 + 48 = 63 g / mol.

m = 63 g / mol × 0.4 mol = 25.2 g.

Answer: 25.2 g.

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