What volume of carbon dioxide will be released when sodium bicarbonate weighing 4.2 g is heated?

Given:
m (NaHCO3) = 4.2 g

To find:
V (CO2) -?

Decision:
1) Write the reaction equation:
2NaHCO3 = (tOC) => Na2CO3 + CO2 ↑ + H2O;
2) Calculate the molar mass of NaHCO3:
M (NaHCO3) = Mr (NaHCO3) = Ar (Na) + Ar (H) + Ar (C) + Ar (O) * 3 = 23 + 1 + 12 + 16 * 3 = 84 g / mol;
3) Calculate the amount of NaHCO3 substance:
n (NaHCO3) = m (NaHCO3) / M (NaHCO3) = 4.2 / 84 = 0.05 mol;
4) Determine the amount of substance CO2:
n (CO2) = n (NaHCO3) / 2 = 0.05 / 2 = 0.025 mol;
5) Calculate the volume of CO2:
V (CO2) = n (CO2) * Vm = 0.025 * 22.4 = 0.56 l.

Answer: The CO2 volume is 0.56 liters.