How much CO2 can be obtained by burning 20 grams of carbon containing 10% impurities?

Let’s find the mass of carbon without impurities.

100% – 10% = 90%.

20 g – 100%,

X – 90%,

X = (20g × 90%): 100% = 18g.

Let’s find the amount of carbon substance.

n = m: M.

M (C) = 12 g / mol.

n = 18 g: 12 g / mol = 1.5 mol.

Let’s compose the reaction equation, find in what quantitative ratios the substances are.

C + O2 = CO2

According to the reaction equation, there is 1 mol of CO2 for 1 mol of C. The substances are in quantitative ratios of 1: 1.

n (CO2) = n (C) = 1.5 mol.

Let’s find the volume of CO2.

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

V = 1.5 mol × 22.4 L / mol = 33.6 L.

Answer: 33.6 liters.