Balance the following equation and determine the voltage across the galvanic cell based on the following:

$C{r}_2{O}_7^{2-}(aq)+C{l}^{-}(aq)C{r}^{3+}(aq)+C{l}_2(g)$

The temperature of the galvanic cell is at $298K$

The concentrations are:

$-[C{r}_2{O}_7^{2-}]=0\mathrm{.}030M,[C{l}^{-}]=0\mathrm{.}045M,[C{r}^{3+}]=0\mathrm{.}856M$