# Question #0dfbd

Mar 22, 2017

Quite easy. Follow the steps below.

#### Explanation:

In a scenario like this, assume you have $100 g$ of the compound.

So for each element, the percent is the total percent of $100 g$.

$N a = 35.4 g$
$A s = 39.1 g$
$O = 25.0 g$

Now, you will convert grams to moles for each element. Find the molar mass of each element from the periodic table and plug in.

$N a = \frac{35.4 g}{1} \cdot \frac{1 m o l}{23 g} = 1.5 m o l$
$A s = \frac{39.1 g}{1} \cdot \frac{1 m o l}{75 g} = 0.5 m o l$
$O = \frac{25.0 g}{1} \cdot \frac{1 m o l}{16 g} = 1.5 m o l$

Now, divide every answer by the smallest number, which in this case is 0.5.

$\frac{1.5 m o l}{0.5 m o l} = 3$

$\frac{0.5 m o l}{0.5 m o l} = 1$

$\frac{1.5 m o l}{0.5 m o l} = 3$

These numbers are going to give you the ratios of the elements in the compound to give you an empirical formula.

$N {a}_{3} A {s}_{1} {O}_{3}$