Caculate the number of atoms in 39.4 g gold. Molar mass of gold is 197g`mole^(-1).`

Explanation

We know that ,
Molar mass = of Avogadro's number of atoms (Molecules).
`=6.-023 xx 10^(23)` atoms.
Given, molar mass of gold =197 `g//mol`
Now
`:. " " 197` g of gold contains `=6.023 xx 10^(23)` atoms
`:.` 1 g of gold contain `=(6.023xx 10^(23))/(197)` atoms
`:. 39 .4`g of gold contains `=(6.023 xx 10^(23) xx39.4)/(197) rArr 1.20 xx 10^(3)` atoms