How to calculate number of atoms of copper present in 19.7g of 22carat gold?

1000gm gold have 84 gms of Copper.

So, 1gm gold have 0.084gm of Copper.

Therefore, 19.7 gm of gold comtains 19.7×0.084 gm of copper.

That is 1.654 gm of copper.

1 mol of coper weighs 63.5 gm and have Avogrado number of atoms.

So 1gm copper have Na/63.5 number of atoms.


Therefore, 1.654gm of copper have(Na×1.654)/63.5 number of atoms.

The answer is
1.654Na/63.5