# How would you determine the empirical formula of a compound found to contain 63.50% silver, 8.25% nitrogen, and the remainder oxygen.?

Oct 25, 2015

The empirical formula is $\text{AgNO"_3}$.

#### Explanation:

Percentages of Ag, N, and O:
$\text{Ag} :$63.50%
$\text{N} :$8.25%
$\text{O} :$28.25%

Since the percentages add up to 100%, we can assume a 100 g sample, and we can rewrite the percentages as mass in grams.

$\text{Ag} :$$\text{63.50 g}$
$\text{N} :$$\text{8.25 g}$
$\text{O} :$$\text{28.25 g}$

We need to determine the number of moles of each element using each element's molar mass, which is the $\textcolor{red}{\text{atomic weight (relative atomic mass) on the periodic table in grams/mole (g/mol)}}$. The molar mass is the mass of one mole of the element.

$63.50 \cancel{\text{g Ag"xx(color(red)(1"mol Ag"))/(color(red)(107.8682cancel"g Ag"))="0.5887 mol Ag}}$

8.25cancel("g N")xx(color(red)(1"mol N"))/color(red)(14.007cancel"g N")="0.589 mol N"

$28.25 \cancel{\text{g O"xx(color(red)(1"mol O"))/(color(red)(15.999cancel"g O"))="1.766 mol O}}$

Determine the mole ratios by dividing the number of moles of each element by the least number of moles.

$\text{Ag} :$(0.5887"mol Ag")/(0.589"mol")=0.999~~1 "mol Ag"

$\text{N} :$(0.589"mol N")/(0.589"mol")="1.00 mol N"

$\text{O} :$(1.766"mol O")/(0.589"mol")="3.00 mol O"

The empirical formula is $\text{AgNO"_3}$. This compound is silver nitrate.