Calculate the volume of hydrogen that can be obtained by dissolving 11.5 g of sodium containing 2% impurities in water.

| February 25, 2021 | education

1. Let’s find the mass of pure sodium without impurities.

100% – 2% = 98%.

11.5 g – 100%,

X – 98%,

X = (11.5g × 98%): 100 = 11.27g.

2.Let’s find the amount of sodium substance by the formula:

n = m: M.

M (Na) = 23 g / mol.

n = 11.27 g: 23 g / mol = 0.49 mol.

3. Let’s compose the reaction equation, find the quantitative ratios of substances.

2Na + H2O = 2NaOH + H2.

According to the reaction equation, there is 1 mole of hydrogen per 2 mol of sodium. The substances are in quantitative ratios of 2: 1. The amount of hydrogen will be 2 times more than the amount of sodium.

n (H2) = 2 n (Na) = 0.49 × 2 = 0.98 mol.

4.V = Vn n, where Vn is the molar volume of the gas, equal to 22.4 l / mol, and n is the amount of substance.

V = 0.98 mol × 22.4 L / mol = 21.95 L.

Answer: 21.95 liters.



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