0,8*400=320g CaCO3 pur
n=m/M=320/100=3,2 moli CaCO3
C=md*100/ms=>md=30*200/100=60g HCl
n=m/M=60/36,5=1,6438 moli HCl
CaCO3 + 2HCl => CaCl2 + CO2 + H2O
1 mol CaCO3........2 moli HCl
x=0,821 moli.................1,6438 HCl
n exces CaCO3 = 3,2-0,821=2,378
m exces = 2,378*100=237,8g CaCO3
nHCl=nCO2=1,6438 moli
VCO2=1,6438*22,4=36,821L CO2