Which of the following is the correct molar mass of boron trifluoride (BF_3)?

• A. 48.81 g/mol
• B. 67.81 g/mol
• C. 10.81 g/mol
• D. 29.81 g/mol

Answer: (B)

Verified step by step guidance

1. Identify the atomic masses of each element in boron trifluoride (BF_3). Use the periodic table to find: boron (B) has an atomic mass of approximately 10.81 g/mol, and fluorine (F) has an atomic mass of approximately 18.998 g/mol.
2. Write the formula for the molar mass of BF_3 as the sum of the atomic masses of one boron atom and three fluorine atoms: \(\text{Molar mass} = (1 \times M_B) + (3 \times M_F)\).
3. Substitute the atomic masses into the formula: \(\text{Molar mass} = (1 \times 10.81) + (3 \times 18.998)\) g/mol.
4. Calculate the total molar mass by performing the multiplication and addition: multiply 3 by the atomic mass of fluorine, then add the atomic mass of boron.
5. Compare the calculated molar mass to the given options to determine which value matches the correct molar mass of BF_3.