Question

Short answer

4.586 x 10²² Au atoms are present in 15g of pure gold.

Step-by-step solution

Step 1- Given data

Mass of gold collected by prospector= 15g

Step 2- Calculating gold atoms

In one mole of gold, there are 6.022 x 102²³ atoms

The atomic weight of gold is 196.66 so 1 mole of gold is 196.966g

So, no of moles in 15g of pure gold = 15/196.966

=0.076155 moles

Now number of molecules = no. of moles x 6.022 x 10²³

= 0.076155 x 6.022 x 10²³

=0.45860 x 10²³ or 4.586 x 10²²