n= m : M [ n=nr.moli ; m=masa subst. ; Mmasa molara ]
a. MCO2=12+2.16=44------> 44g/moli
n=4g : 44g/moli=0,09 moli CO2
b. MCaCO3=40+12+3.16=100----->100g/moli
n=25g : 100g/moli=0,25 moli CaCO3
c. MSO3=32 +3.16=80------> 80g/moli
n=320g : 80g/moli=4 moli SO3
d. MHNO3=1+14+3.16=63------->63g/moli
n=63g : 63g/moli=1mol HNO3