Calculate the volume of CO2 evolved at NTP when 20g of CaCO3 is heated strongly.
4.48
The question gives weight of reactants and asks the volume of product. So, it is a weight-volume problem. Start by balancing the reaction
CaCO3 → CaO + CO2(g) ↑
∴ 1 mole of CaCO3 gives 1 mole of CO2
From Avagadro's Law, 1 mole of CO2 at NTP occupies 22.4L
∴ 1 mole of CaCO3 = 22.4 L of CO2
100g = 22.4L of CO2
∴ 20g = 20 × 22.4100 = 4.48 L of CO2