Question

A) How many moles of gold atoms are present in a 295-gram sample of gold? B) How many gold atoms would there be in the sample?

Answer 1

5 gram of 197 Au contain 1.53*10^22 atoms. so just multiply that with 59 to get 295 grams :)

Answer 2

The molar mass of gold, Au, as seen on the periodic table, is 196.97 grams per mole. So, do this to find the number of moles in a 295 gram sample:


`(295g\ Au)((1mol\ Au)/(196.97g\ Au)) = 1.49769mol\ Au`

So, a 295 gram sample of gold has about 1.5 moles of gold in it.

To find the number of atoms, multiply the number of moles by Avogadro's number:


`(1.49769mol\ Au)((6.022*10^(23)\ atoms)/(mol)) = 9.02 * 10^(23)\ atoms\ Au`