What is the molar mass of barium hydroxide, Ba(OH)_2?

• A. 155.32 g/mol
• B. 171.34 g/mol
• C. 189.36 g/mol
• D. 137.33 g/mol

Answer: (B)

Verified step by step guidance

1. Identify the chemical formula of barium hydroxide, which is Ba(OH)\_2. This means the compound contains 1 atom of barium (Ba), 2 atoms of oxygen (O), and 2 atoms of hydrogen (H).
2. Find the atomic masses of each element from the periodic table: Barium (Ba) ≈ 137.33 g/mol, Oxygen (O) ≈ 16.00 g/mol, Hydrogen (H) ≈ 1.008 g/mol.
3. Calculate the total mass contributed by each element in the formula: For Ba, multiply 1 by its atomic mass; for O, multiply 2 by its atomic mass; for H, multiply 2 by its atomic mass.
4. Add all these masses together to get the molar mass of Ba(OH)\_2 using the formula: \(\text{Molar mass} = (1 \times M_{Ba}) + (2 \times M_{O}) + (2 \times M_{H})\).
5. Sum the values from the previous step to find the total molar mass of barium hydroxide in grams per mole.