M(H2SO4)=2xA(H)+A(S)+4xA(O)=2+32+64=98, unde M(H2SO4)=masa atomica a H2SO4 si A(H)= numarul de masa a H
Compozitia procentuala a H2SO4:
Dca in 98g H2SO4.....2g H....32g S....64g O
Atunci in 100g H2SO4....x g H...y g S...z g O
Rezulta ca x=2x100/98=2.04 % H, y=32x100/98=32.65% S si z=64x100/98=65.3% O
Daca un mol de H2SO4 are 98g rezulta ca 5 moli au 98x5=490g, iar 2 moli au 98x2=196g.
M(Na2CO3)=2xA(Na)+A(C)+3xA(O)=23x2+12+64=122
Daca 1 mol Na2CO3.......122g
Atunci x moli ..................80g
Rezulta x=0.65 moli
