Question

Determinati cantitatea(moli,grame) de hidroxid de sodiu care se consuma cand reactioneaza cu 490 de grame solutie de acid sulfuric de concentratie 10 %.

Answer 1

-calculez masa acidului dizolvat in solutie
c=mdx100/ms
10=mdx100/490---> md= 49g H2SO4
- calculez moli acid
n=m/M
n= 49g/98g/mol= 0,5molH2SO4-
-deduc moli de baza ,din ecuatia reactiei. apoi,masa

2mol..............1mol
2NaOH   + H2SO4----> Na2SO4  + 2H2O
x..................0,5mol
x=1molNaOH
m=nxM
m= 1molx 40g/mol= 40g NaOH