p = 60%
p = m pur/ m impur*100 ⇒ m pur = p*mimpur/100 = 60*500/100 = 300g CaCO₃
MCaCO₃ = 100g/mol   ,  n = m/M = 300/100 = 3 moli CaCO₃
CaCO₃ ⇒ CaO + CO₂↑
n CaCO₃ = nCO₂ = 3 moli
m COâ‚‚ = 3*44 = 132g
VCOâ‚‚ (c.n) = 3*22,4 = 67,2L
MCOâ‚‚ = 44g/mol