(a) CO2 has molar mass = 44 g mol-1
5 moles of Co2 have molar mass = 44 x 5 = 220 g
H20 has molar mass = 18 g mol-1
5 moles of H2O have mass = 18 × 5 g = 90 g
(b) Number of moles in 240 g Ca metal = 240/40 = 6
Number of moles in 240 g of Mg metal = 240/24 = 10
Ratio is 6 : 10
Or, 3 : 5