Răspuns:

1.

100gCaCO3.........85gpur

500gCaCO3........xgpur

x=500×85/100=425g CaCO3 pur

MCaCO3 =40+12+3×16=100g/mol

MCaO=40+16=56g/mol

100g 56g

CaCO3 => CaO + CO2

425g xg

x=425×56/100=calculează