What is the molar mass of ammonia (NH_3)?

• A. 17.0 g/mol
• B. 15.0 g/mol
• C. 18.0 g/mol
• D. 16.0 g/mol

Answer: (A)

Verified step by step guidance

1. Identify the chemical formula of ammonia, which is NH_3, meaning it contains 1 nitrogen (N) atom and 3 hydrogen (H) atoms.
2. Find the atomic masses of nitrogen and hydrogen from the periodic table: nitrogen has an atomic mass of approximately 14.0 g/mol, and hydrogen has an atomic mass of approximately 1.0 g/mol.
3. Calculate the total mass contributed by nitrogen: multiply the number of nitrogen atoms by its atomic mass: \$1 \times 14.0 = 14.0$ g/mol.
4. Calculate the total mass contributed by hydrogen: multiply the number of hydrogen atoms by its atomic mass: \$3 \times 1.0 = 3.0$ g/mol.
5. Add the masses of nitrogen and hydrogen to find the molar mass of ammonia: \$14.0 + 3.0 = 17.0$ g/mol.