Which of the following gases would behave the most like an ideal gas when confined to a 5.0 L container at 1 atm and 300 K?

• A. H_2O
• B. CO_2
• C. NH_3
• D. He

Answer: (D)

Verified step by step guidance

1. Recall that ideal gas behavior is best approximated by gases with small, nonpolar molecules and weak intermolecular forces, especially under conditions of low pressure and high temperature.
2. Consider the molecular properties of each gas: H_2O is polar and forms hydrogen bonds, CO_2 is linear and nonpolar but has stronger dispersion forces due to its larger size, NH_3 is polar and can form hydrogen bonds, and He is a noble gas with very weak intermolecular forces and a very small atomic size.
3. Understand that the ideal gas law assumes no intermolecular forces and that the gas particles occupy negligible volume; deviations occur when these assumptions fail.
4. Evaluate the conditions given: 5.0 L container, 1 atm pressure, and 300 K temperature, which are relatively moderate and favor ideal behavior, but differences in molecular interactions still matter.
5. Conclude that helium (He), being a monatomic noble gas with minimal intermolecular forces and very small particle size, will behave the most like an ideal gas under these conditions.