Question

How many atoms or molecules are present in $1.0$ mol of $Au$? How am I able to find the answer?

Answer 1

You use the fact that $41$ mole of any substance contains exactly ${\mathrm{6.022.10}}^{23}$ atoms or molecules of that substance, this is known as Avogadro's number.

In your case $1$ mole of gold will have exactly ${\mathrm{6.022.10}}^{23}$ atoms of gold.

$1.0$ mole $.\frac{{\mathrm{6.022.10}}^{23}}{1mole}={\mathrm{6.022.10}}^{23}$ atoms of $Au$

If round the answer to two sign figs, the number of sign figs in $1.0$ you'll get:

$1.0$ mole $Au={\mathrm{6.0.10}}^{23}$ atoms $Au$