# How do I find the mass of potassium in a 50.0*g mass of potassium sulfate?

Sep 7, 2015

Divide the mass by the molar mass.

#### Explanation:

Molecular mass ${\text{K"_2"SO"_4 = "174.26 g·mol}}^{-} 1$.

You can find this by adding the atomic masses of all the atoms that make up the molecule -- you can find these in the periodic table.

You have $\text{50.0 g}$.

Divide the second value by the first.

(50.0 color(red)(cancel(color(black)("g"))))/(174.26 color(red)(cancel(color(black)("g")))"·mol"^-1)= "0.287 mol" of ${\text{K"_2"SO}}_{4}$

Now remember to multiply this answer by $2$, because there are two $\text{K}$-atoms per molecule, so the final answer is $0.574 m o l$ of $\text{K}$