Question

Va rog mult,ma puteti ajuta doar cu exercitiul 2 punctul b?

Answer 1

din ecuatia reactiei
1mol......................7mol
K2Cr2O7 + 6KI + 7H2SO4---> 4K2SO4+ Cr2(SO4)3 +3I2 + 7H2O
  calculez masa de acid dizolvat in solutia data
c=mdx100/ms---> md= 60x500/100g= 300g

n(niu),H2SO4=m/M= 300g/98g/mol=3,06mol

revin la ecuatie.  1mol dicromat.........7mol acid
                              x...........................3,06
x= n,dicromat=0,437 mol

c,m= n/V(L)----> V=0,4373/0,1 L= 4,373L