-calculez masa de acid dizolvata in solutie
c/100=md/ms
20/100=md/250------> md=50gHNO3;
M= 63g/mol HNO3
ECUATIA REACTIEI
2mol............................1mol
Ca+ 2HNO3---> Ca(NO3)2+ H2
2x63g.................................22,4 l
50g......................................V=-----------------> calculeaza !!!!