CaCO3 --> CaO + CO2
MCaCO3=100g/mol
MCaO=56g/mol
100g CaCO3.......................56g CaO
xg..;......................................336g CaO
x=100*336/56=600g CaCO3 (pur)
puritatea = masa pura/ masa impura*100 => masa impura=masa pura*100/puritate = 600*100/20=3000g CaCO3 = 3kg CaCO3