Which gas sample has the greatest volume at STP?

• A. 10.0 g He
• B. 10.0 g Ne
• C. 10.0 g N
• D. All have the same volume

Answer: (A)

Verified step by step guidance

1. First, understand that STP (Standard Temperature and Pressure) conditions are defined as 0°C (273.15 K) and 1 atm pressure. At STP, 1 mole of any ideal gas occupies 22.4 liters.
2. Next, calculate the number of moles for each gas sample using the formula: \( \text{moles} = \frac{\text{mass}}{\text{molar mass}} \).
3. Determine the molar mass of each gas: Helium (He) is approximately 4.00 g/mol, Neon (Ne) is approximately 20.18 g/mol, and Nitrogen (N) is approximately 14.01 g/mol.
4. Calculate the moles for each gas: \( \text{moles of He} = \frac{10.0 \text{ g}}{4.00 \text{ g/mol}} \), \( \text{moles of Ne} = \frac{10.0 \text{ g}}{20.18 \text{ g/mol}} \), \( \text{moles of N} = \frac{10.0 \text{ g}}{14.01 \text{ g/mol}} \).
5. Finally, compare the number of moles for each gas. The gas with the greatest number of moles will have the greatest volume at STP, since volume is directly proportional to the number of moles.