Question

How many atoms are in `"1.5 mol HCl"`?

Answer 1

There are `1.8xx10^24` atoms in 1.5 mol HCl.

Explanation:

One mole of anything is `6.022xx10^23` of anything, including molecules.

`1.5color(red)cancel(color(black)("mol HCl"))xx(6.022xx10^23"molecules HCl")/(1color(red)cancel(color(black)("mol HCl")))=9.0xx10^23"molecules HCl"`

Every `"HCl"` molecule contains two atoms, H and Cl.

`9.0xx10^23color(red)cancel(color(black)("molecules HCl"))xx(2"atoms")/(1color(red)cancel(color(black)("molecule HCl")))=1.8xx10^24" atoms"` rounded to two significant figures