Question #dd146

1 Answer
Oct 19, 2015

"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 "107.8682 g/mol". This tells you that one mole of silver has a mass of "107.8682 g".

"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 = color(green)("9.3 moles Ag")