Calculate the mass of CaCO3 obtained by reacting 20 liters of CO2 containing 10% impurities with calcium oxide.

Given:

V (CO2) = 20 l

w% (impurities) = 10%

To find:

m (CaCO3) -?

Decision:

CaO + CO2 = CaCO3, – we solve the problem based on the composed reaction equation:

1) Find the volume of pure carbon dioxide that has reacted:

If the proportion of impurities = 10%, then the proportion of pure gas is 90%

V (CO2) = 20 l * 0.9 = 18 l

2) Find the amount of substance:

n (CO2) = V: Vm = 18 L: 22.4 L / mol = 0.8 mol

3) We compose a logical expression:

If 1 mol of CO2 gives 1 mol of CaCO3,

then 0.8 mol of CO2 will give x mol of CaCO3,

then x = 0.8 mol.

4) Find the mass of the substance formed during the reaction:

m (CaCO3) = n * M = 0.8 mol * 100 g / mol = 80 g.

Answer: m (CaCO3) = 80 g.