Question

The volume in litres of CO2 liberated at STP, when 10g of 90% pure limestone is heated completely is?

Answer 1

chemical formula of limestone is CaCO3.

so, molar mass of limestone = atomic mass of Ca + atomic mass of C + 3 × atomic mass of O

= 40 + 12 + 48

= 100g/mol

given, 10g of 90% pure limestone.

so, mass of pure limestone = 10 - 90% of 10 = 9g

no of mole of Limestone = 9/100 = 0.09

now, limestone is heated completely then, reaction is ...

CaCO3 ===> CaO + CO2

here we see , one mole of CO2 is evolved by one mole of limestone.

so, 0.09 mole of CO2 gas is evolved by 0.09 mole of limestone.

we know,

volume of 1mol of gas at STP = 22.4L

so, volume of 0.09mol of CO2 gas at STP = 22.4 × 0.09 = 2.016L