help with chemistry please!!! voltaic cell?

Consider a voltaic cell in which the following reaction occurs: Zn(s) + Sn2 + (aq) ---> Zn2 + (aq) + Sn (s) a) calculate E* for the cell. b) when the cell operates, what happens to the concentration of Zn^2+? The concentration of Sn^2+? c) when the cell voltage drops to zero, what is the ratio of the concentration of Zn^2+ tp that of Sn^2+? d) If the concentration of both cations is 1.0 M originally, what are the concentrations when the voltage drops to zero? please help me with this i don't understand it