Question

How many atoms are in 8.00 mol of `CO_2` molecules?

Answer 1

`1.45 * 10^(25)"atoms"`

Explanation:

The idea here is that each molecule of carbon dioxide is made up of `3` atoms

• one atom of carbon, `1 xx "C"`
• two atoms of oxygen, `2 xx "O"`

This means that each mole of carbon dioxide will contain `3` moles of atoms.

• one mole of carbon atoms, `1 xx "C"`
• two moles of oxygen atoms, `2 xx "O"`

This, of course, implies that `8.00` moles of carbon dioxide molecules will contain

`8.00 color(red)(cancel(color(black)("moles CO"_2))) * "3 moles atoms"/(1color(red)(cancel(color(black)("mole CO"_2)))) = "24.0 moles atoms"`

Now all you have to do is convert the number of moles to number of atoms by using Avogadro's constant

`24.0 color(red)(cancel(color(black)("moles"))) * overbrace((6.022 * 10^(23)"atoms")/(1color(red)(cancel(color(black)("mole")))))^(color(blue)("Avogadro's constant")) = color(green)(bar(ul(|color(white)(a/a)color(black)(1.45 * 10^(25)"atoms")color(white)(a/a)|)))`

The answer is rounded to three sig figs.