Răspuns:
C+ O2=> CO2
CO2+ H2O => H2CO3
2Mg+ O2=> 2MgO
MgO + H2O => Mg(OH)2
MgCO3=> MgO + CO2
100g MgCO3.......77,5g pur
1280gMgCO3........x g pur
x=1280×77,5/100=992g MgCO3 pur
MMgCO3 =24+12+3×16=84g/mol
MMgO=24+16=40g/mol
84g 40g
MgCO3 => MgO + CO2
992g xg
x=992×40/84=472,38g MgO
