chemistry
posted by MARY .
Balance this chemical equation.
Cr2O7 2(aq) + Cu(s)> Cr3+(aq) +Cu2+aq)
I don't understand how to do this problem. Where do i begin? thank you.

Where do you start? By assigning oxidation numbers to each of the elements to determine which have changed. Here is a hint to get you started. Cr changes from +6 for EACH Cr on the left to +3 on the right. Cu changes from zero on the left to +2 on the right.
You need to learn to do these redox equations yourself. Here is a site that tells you almost anything you want to know about redox equation.
http://www.chemteam.info/Redox/Redox.html
If you have specific questions as you go through I'll be more than happy to help you through.