# What is the percentage "ammonium" content in "ammonium dichromate"?

Jan 27, 2017

In ${\left(N {H}_{4}\right)}_{2} C {r}_{2} {O}_{7}$............?

#### Explanation:

The molecular mass of $\text{ammonium dichromate}$ is $252.07 \cdot g \cdot m o {l}^{-} 1$. We nominate the $N {H}_{4}^{+}$ unit as the cation. This has a mass of $18.04 \cdot g \cdot m o {l}^{-} 1$.

And thus percentage of cation by mass is:

(2xx18.04*g*mol^-1)/(252.07*g*mol^-1)xx100%~=14%.

What is the percentage by mass of metal?