1. Calcium carbonate is decomposed on heating in the following reaction
CaCO₃ → CaO + CO₂
i. How many moles of Calcium carbonate are involved in this reaction?
ii. Calculate the gram molecular mass of calcium carbonate involved in this reaction.
iii. How many moles of CO₂ are there in this equation?

Calculation based on number of moles from mass and volume
i) Calculate the number of moles in 46 g of sodium?
ii) 5.6 litre of oxygen at S.T.P
iii) Calculate the number of moles of a sample that contains 12.046 × 10²³ atoms of iron?

Calculation based on number of atoms/molecules
i) Calculate the number of molecules in 11.2 litre of CO₂ at S.T.P
ii) Calculate the number of atoms present in 1 gram of gold (Atomic mass of Au = 198)
iii) Calculate the number of molecules in 54 gm of H₂O?
iv) Calculate the number of atoms of oxygen and carbon in 5 moles of CO₂.

Calculation based on molar volume
Calculate the volume occupied by:
i) 2.5 mole of CO₂ at S.T.P
ii) 12.046 × 10²³ of ammonia gas molecules
iii) 14 g nitrogen gas

Calculate the percentage of sulphur in H₂SO₄.