# The molar mass of fluorine is 19.00 g/mol and that of aluminium is 26.98 g/mol. How do you calculate the molar mass of aluminium fluoride?

Mar 13, 2017

The molar mass of aluminium fluoride is 83.98 g/mol.

#### Explanation:

The formula of aluminium fluoride is ${\text{AlF}}_{3}$.

This tells us that one formula unit of ${\text{AlF}}_{3}$ contains one atom of $\text{Al}$ and three atoms of $\text{F}$.

It also tells us that one mole of contains one mole of $\text{Al}$ atoms and three moles of $\text{F}$ atoms.

Thus, we can calculate the molar mass of ${\text{AlF}}_{3}$ as follows:

$\text{Mass of 1 mol" = 1 color(red)(cancel(color(black)("mol Al"))) × "26.98 g"/(1 color(red)(cancel(color(black)("mol Al")))) + 3 color(red)(cancel(color(black)("mol F"))) × "19.00 g"/(1 color(red)(cancel(color(black)("mol F")))) = "26.98 g + 57.00 g" = "83.98 g}$