# Which is the molar mass of #BF_3#?

##### 1 Answer

Jul 17, 2016

#### Explanation:

**** #"number of atoms given by subscript"# #xx# #"atomic weight of element"# #=# molar mass**

First, you want to have a periodic table available so you can determine the atomic weight of B and F:

- B has an atomic weight of 10.811 g/mol
- F has an atomic wight of 19.00 g/mol

From the chemical formula, we have 1 boron atom, so the atomic mass would just be 10.811 g/mol

Next, you have 3 fluorine atoms, so you would multiply the atomic mass of F by 3 to obtain an atomic weight of 57.00 g/mol

Now you want to add the mass of each atom together to obtain the molar mass of the entire compound: