Intai, calculam cantitatea de CO2 obtinuta din descompunerea calcarului (CaCO3)
p/100=mpura/mimpura => mpura=p*impura/100
p=100-20=80%
mpura=80*2000/100=1600g CaCO3 pur
100g........................1mol
CaCO3 -> CaO + CO2
1600g...................16moli
12g.............1mol
C + O2 -> CO2
x=?.............16moli
x=16*12=192g C
192g C.............60%
mcarbune......100%
mcarbune=192*100/60=320g carbune