Calculate the molecular mass of CaCO3 (At mass Ca = 40 u, C = 12 u, O = 16 u)

Dhanalakshmi · June 27, 2019, 4:53am

(i) Calculate the molecular mass of CaCO₃ (At mass Ca = 40 u, C = 12 u, O = 16 u)
(ii) Verify by calculating that
(a) 5 moles of CO₂ and 5 moles of H₂O do not have the same mass
(b) 240 g of calcium and 240 g of magnesium elements have a mole ratio of 5:3 (At mass H = 1u, Ca = 40u, Mg = 24u)

Dhanalakshmi · June 27, 2019, 4:56am

(i) Molecular mass of CaCO₃ = 40 × 1 + 1 × 12 + 3 × 16
= 40 + 12 + 48
= 100 u.

(ii) (a) CO₂ has molar mass = 44 g mol^-1
5 moles have molar mass = 44 × 5
= 220 g
H₂O has molar mass = 18 g mol^-1
= 90 g.