The two most common oxidation states are Cr(III) and Cr(VI). Balance the following oxidation-reduction equations that involve one of these oxidation states of chromium. Assume that the reactions occur in acidic solution.

A. Cr(s) + O2 (g) + H^+ <-> Cr^3+

B. Fe^2+ (aq) + Cr2O7^2- (aq) <-> Fe^3+ (aq) + Cr^3+ (aq)

C. BrO3- (aq) +Cr^3+ (aq) <-> Br2 (aq) + HCrO4- (aq)

I know the steps of solving one of these but I can't seem to get these equations to fit. Please help

2 answers

All I can do is to balance these for you and that won't help you at all. If you want to show what you have, especially for the one you know, perhaps we can help. Here is a site that may help, also.
http://www.chemteam.info/Redox/Redox.html

In 1, Cr goes from zero on the left to 3+ on the right. Oxygen is zero on the left
I just know the 6 steps to balance:
1. identification
2. balance mass
3. balance oxygen
4. balance hydrogen
5. balance charge
6. combine