# Question dd146

Oct 19, 2015

$\text{9.3 moles}$

#### Explanation:

To find how many moles you get in one kilogram of silver you need to use silver's molar mass.

A substance's molar mass tells you what the exact mass of one mole of that substance is.

In silver's case, its molar mass is listed as $\text{107.8682 g/mol}$. This tells you that one mole of silver has a mass of $\text{107.8682 g}$.

$\text{1 mole of Ag" -> "107.8682 g}$

All you have to do now is figure out how many moles would fit, so to speak, in one kilogram. Convert this mass from kilograms to grams first

1color(red)(cancel(color(black)("kg"))) * "1000 g"/(1color(red)(cancel(color(black)("kg")))) = "1000 g"

This means that you have

1000color(red)(cancel(color(black)("g Ag"))) * "1 mole Ag"/(107.8682 color(red)(cancel(color(black)("g Ag")))) = "9.2706 moles Ag"#

of silver in one kilogram of silver.

I'll round this number off to two sig figs to get

$n = \textcolor{g r e e n}{\text{9.3 moles Ag}}$