At standard temperature and pressure (STP), what volume will 35.9 g of hydrogen gas (H_2) occupy?

• A. 2.0 L
• B. 18.0 L
• C. 22.4 L
• D. 400 L

Answer: (D)

Verified step by step guidance

1. Identify the molar mass of hydrogen gas (H\_2). Since each hydrogen atom has an atomic mass of approximately 1.0 g/mol, the molar mass of H\_2 is calculated as \$2 \times 1.0 = 2.0$ g/mol.
2. Calculate the number of moles of hydrogen gas using the formula: \(\text{moles} = \frac{\text{mass}}{\text{molar mass}}\). Substitute the given mass (35.9 g) and the molar mass (2.0 g/mol) to find the moles of H\_2.
3. Recall that at standard temperature and pressure (STP), one mole of any ideal gas occupies 22.4 liters. This is a key concept in gas calculations.
4. Use the relationship between moles and volume at STP to find the volume occupied by the hydrogen gas: \(\text{volume} = \text{moles} \times 22.4\) L/mol.
5. Substitute the number of moles calculated in step 2 into the equation from step 4 to find the volume of hydrogen gas at STP.