Question

how many atoms of hydrogen are there in 4.5 moles of hydrogen

Answer 1

We are asked to determine the number of atoms in 4.5 moles of hydrogen. To do that we will Avogadro's number:

$1mol=6.023\times10^{23}atoms$

Using the conversion we get:

$4.5mol\times\frac{6.023\times10^{23}atoms}{1mol}=27.1\times10^{23}atoms$