[kdpk]

fe(2+) + Cr2O7 (2-) -----------> Fe (3+) + Cr (3+)

9 (Fe (2+) ------------> Fe (3+) + e-)

9e- + 14H(+) + Cr2O7 (2-) ------------> Cr (3+) + 7H2O

=

9Fe(2+) -----> 9Fe(3+) + 9e-
9e- + 14H(+) + Cr2O7 (2-) ------------> Cr (3+) + 7H2O

And now I just cancell out?

i cant balance the charges no matter what i do pls help 

[Albert]

9e- + 14H(+) + Cr2O7 (2-) ------------> Cr (3+) + 7H2O

The number of electrons is wrong: what are the oxidation numbers of chromium in the reagents and in the products?

[Borek]

Problem is not in the number of electrons, but in the lost chromium. Wrong number of electrons is just a side effect of trying to balance charge

[Sat87]

Looks like your product is missing a Cr molecule
 


9Fe²⁺+14H ⁺+Cr₂O₇^2----------------------> 9Fe³⁺+ Cr³⁺+ 7H²O

         On the right we have                                                          On the left we have
Fe:9 H:14 Cr:2 O:7                                Fe:9 H:14 Cr:1 O:7

Check your initial equation again just to make sure its right