Explanation: 1. Determine the atomic weight of B and F 2. B has an atomic weight of 10.811 g/mol and F has an atomic wight of 19.00 g/mol 3. From the chemical formula, we have 1 boron atom, so the atomic mass would just be 10.811 g/mol 4. 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 5. Now you want to add the mass of each atom together to obtain the molar mass of the entire compound: 10.811 g/mol + 57.00 g/mol = 67.81 g/mol