## Chemistry: The Molecular Science (5th Edition)

$[K^+] = 0.0318M$ $[Cr_2O{_7}^{2-}] = 0.0159M$
As we calculated in the last exercise, the molarity of $K_2Cr_2O_7$ is equal to $0.0159M.$ There are 2 $K^+$ in each $K_2Cr_2O_7$, so: $[K^+]=2 \times 0.0159M=0.0318M$ There is 1 $Cr_2O{_7}^{2-}$ in each $K_2Cr_2O_7$, so: $[Cr_2O{_7}^{2-}]=1 \times 0.0159M=0.0159M$