What is the percent by mass of hydrogen in NH_3 if the gram formula mass is 17.0 grams?

• A. 23.5%
• B. 17.6%
• C. 5.9%
• D. 82.4%

Answer: (B)

Verified step by step guidance

1. Identify the molecular formula of ammonia, which is NH_3, meaning it contains 1 nitrogen atom and 3 hydrogen atoms.
2. Determine the atomic masses of nitrogen and hydrogen from the periodic table: nitrogen (N) is approximately 14.0 g/mol, and hydrogen (H) is approximately 1.0 g/mol.
3. Calculate the total mass of hydrogen in one mole of NH_3 by multiplying the number of hydrogen atoms by the atomic mass of hydrogen: \$3 \times 1.0$ g/mol.
4. Use the given gram formula mass of NH_3, which is 17.0 g/mol, to find the percent by mass of hydrogen using the formula: \(\text{Percent by mass of H} = \left( \frac{\text{mass of H}}{\text{molar mass of NH}_3} \right) \times 100\%\).
5. Substitute the values into the formula and simplify the expression to find the percent by mass of hydrogen in NH_3.