[zhinkk]

Cu2+ (aq) + I- (aq)-> Cul (s) + I2 (s)

I'm having troubles balancing it. The correct coefficients are 2 4 2 1. Can someone guide me through this one please? It's a SAT problem.

[Borek]

This is a redox problem, so if simple inspection fails, use one of the methods for redox reactions.

http://www.chembuddy.com/?left=balancing-stoichiometry&right=balancing-redox

http://www.chembuddy.com/?left=balancing-stoichiometry&right=half-reactions-method

http://www.chembuddy.com/?left=balancing-stoichiometry&right=oxidation-numbers-method

[Vidya]

Cu2+ (aq) + I- (aq)-> Cul (s) + I2 (s)

I'm having troubles balancing it. The correct coefficients are 2 4 2 1. Can someone guide me through this one please? It's a SAT problem.

Follow these steps
write it in two half reactions
balance atoms (other than H and O )
in your case there are no H and O
so just balance the charges by adding electrons
equalize the number of electrons lost or gained.
add two balance half reactions
Try these steps