Which of the following samples of N_2 contains the greatest mass?

• A. 56 grams of N_2
• B. 2.0 moles of N_2
• C. 1.0 mole of N_2
• D. 44.8 liters of N_2 at STP

Answer: (B)

Verified step by step guidance

1. Identify the molar mass of nitrogen gas (N_2). Since each nitrogen atom has an atomic mass of approximately 14 g/mol, the molar mass of N_2 is calculated as \$14 \times 2 = 28$ g/mol.
2. Convert each given quantity into mass (grams) to compare them directly:
3. - For 56 grams of N_2, the mass is already given as 56 g.
4. - For 2.0 moles of N_2, use the formula \(\text{mass} = \text{moles} \times \text{molar mass}\), so mass \(= 2.0 \times 28\) g.
5. - For 1.0 mole of N_2, similarly, mass \(= 1.0 \times 28\) g.
6. - For 44.8 liters of N_2 at STP, use the molar volume of a gas at STP (22.4 L/mol) to find moles: \(\text{moles} = \frac{44.8}{22.4} = 2.0\) moles, then convert to mass using \(\text{mass} = 2.0 \times 28\) g.