Calculate the volume of sulfur dioxide (SO2) and how many molecules of potassium

| August 7, 2021 | education

Calculate the volume of sulfur dioxide (SO2) and how many molecules of potassium sulfite are formed during the decomposition of 180 g of potassium hydrogen sulfite (KHSO3).

Given:

m (KHSO3) = 180 g.

V (SO2) -?

N (K2SO3) -?

Solution:

Let’s find the amount of the substance KHSO3.

n = m: M.

M (KHSO3) = 120 g / mol.

n = 180 g: 120 g / mol = 1.5 mol.

Let’s find the quantitative ratios of substances.

2KHSO3 = K2SO3 + SO2 + H2O.

For 2 mol of KHSO3, there is 1 mol of SO2.

Substances are in quantitative ratios of 2: 1.

n (SO2) = ½ n (KHSO3) = 1.5: 2 = 0.75 mol.

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

V = 0.75 mol × 22.4 L / mol = 16.8 L.

N = n × NA, NA – Avogadro’s number, 6 × 10 ^ 23.

For 2 mol of KHSO3, there is 1 mol of K2SO3.

n (K2SO3) = ½ n (KHSO3) = 1.5: 2 = 0.75 mol.

N = 0.75 mol × 6 × 10 ^ 23 = 4.5 × 10 ^ 23.

Answer: 4.5 × 10 ^ 23; 16.8 l.



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