# Question #2e4a2

Oct 23, 2016

$1.81$x${10}^{24}$ atoms (3 s.f.)

#### Explanation:

Recall that moles can be converted to particles using Avogadro's constant ($6.022 \cdot {10}^{23}$) which is the number of molecules per mole of a substance.

In $1.5$ moles of fluorine gas, there are $1.5 \cdot 6.022 \cdot {10}^{23}$ molecules of gas. However, since fluorine is diatomic (${F}_{2}$), each molecule contains two atoms of fluorine. Thus, the number of atoms in $1.5 m o l$ of ${F}_{2}$ is twice the number of molecules.

$\therefore$ No. of atoms $= 2 \left(1.5 \cdot 6.022 \cdot {10}^{23}\right) = 1.8066 \cdot {10}^{24}$

$= 1.81 \cdot {10}^{24}$ (3 s.f.), since there are 3 s.f. in $1.50$.