[petstar21]

SO Ive been trying to figure this out for many hours now and am very irritated. I understand the 2 half reaction way and if many things in the eqaution then the reox ones (elements that change charge way) but I cant get this one:

Cr2O7 (charge of 2-) + SO3 (charge of 2-) ---> Cr3+ + SO4 (charge of 2-)

please help and if you can explain more about this difficult topic that would be great. thanks!

[Borek]

Show what you did so far and we will push you in the right direction.

[petstar21]

I set Cr2O7 2- ---> Cr 3+

and SO3 2-  ----> SO4 2-

for the cr's i put
14H+ + Cr2O7 2- ---> 2Cr 3+ + 7 H2O
and then for the charge I put
I put +9e- on the left

for the So's I did
H2O+ SO3 2-  ----> SO4 2- + 2H+
and for the charge it had to be -1 so you dont add anything??

and after that i got lost!

[Borek]

14H+ + Cr2O7 2- ---> 2Cr 3+ + 7 H2O
and then for the charge I put
I put +9e- on the left

14 - 6 = 9?

for the So's I did
H2O+ SO3 2-  ----> SO4 2- + 2H+
and for the charge it had to be -1 so you dont add anything??

You -2 on the left and 0 on the right - you have to add 2 electrons somewhere.