Which of the following best describes the difference between a real gas and an ideal gas?

• A. Real gases always obey the equation PV = nRT under all conditions, while ideal gases do not.
• B. Ideal gases are assumed to have no intermolecular forces and occupy no volume, while real gases have intermolecular forces and occupy finite volume.
• C. Ideal gases can be liquefied at low temperatures, but real gases cannot.
• D. Real gases consist only of monoatomic particles, while ideal gases are always diatomic.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of an ideal gas. An ideal gas is a theoretical gas composed of many randomly moving point particles that interact only when they collide elastically. It is assumed to have no intermolecular forces and that the particles occupy no volume.
2. Step 2: Understand the concept of a real gas. Real gases deviate from ideal behavior because their particles have finite volume and experience intermolecular forces such as attraction and repulsion.
3. Step 3: Recall the ideal gas law equation: \(PV = nRT\), which describes the behavior of an ideal gas under various conditions of pressure (P), volume (V), amount of substance (n), gas constant (R), and temperature (T).
4. Step 4: Recognize that real gases do not always obey the ideal gas law perfectly, especially at high pressures and low temperatures, due to the effects of particle volume and intermolecular forces.
5. Step 5: Compare the given options by focusing on the key differences: ideal gases assume no volume and no intermolecular forces, while real gases have both finite volume and intermolecular forces. This distinction best describes the difference between real and ideal gases.