Question

o proba de alama reactioneaza cu 300 ml solutie acid clorhidric 14,6la suta cu densitatea 1gram/cm cub.Determina masa probei daca contine 70la suta cupru si 30 la suta zinc

Answer 1

ro=ms/V=>ms=ro*V=1*300=300g sol. HCl

C=md/ms*100=>md=C*ms/100=14,6*300/100=43,8g HCl

Doar Zincul (Zn) reactioneaza cu HCl:

Zn + 2HCl => ZnCl2 + H2

65g Zn........................2*36,5g HCl
xg Zn............................43,8g HCl

x=65*43,8/73=39g Zn (30%)

39g.................................30%
xg....................................70%

x=39*70/30=91g Cu

m proba = 91+39=130g

Parerea mea..