Question

What is the molar mass of phosphorus?

Answer 1

`123.88 "g"/"mol"`

Explanation:

Step 1. Determine how many of each type of atom there are in the chemical formula `"P"_4`

`" "`In this case, there are 4 phosphorous atoms per molecule

Step 2. Determine the mass of phosphorous from the periodic table

Because the atomic mass of phosphorous is 30.97 amu, we can say the mass is

`m=4xx30.97=123.88 "g"/"mol"`

This means that 1 mol of `"P"_4` weighs 123.88 grams.

[NOTE: If you only wanted the molar mass of single atoms of phosphorous, then `m=30.97 "g"/"mol"`; That is a mole of isolated phosphorous atoms would weigh 30.97 grams.]