Răspuns:
100gCuCO3........................40g pur
250gCuCO3........................xg pur
x=250×40/100=100g pur
MCuCO3=64+12+3×16=124g/mol
MCuO=64+16=80g/mol
124g.............80g
CuCO3 → CuO + CO2↑
100g...............yg
y=100×80/124=64,51gCuO
Explicație: