Real gas

Definition

A real gas is a gas that does not behave ideally due to interactions between its molecules and the volume occupied by them. Unlike ideal gases, which follow the ideal gas law strictly under all conditions, real gases exhibit deviations from this behavior at high pressures and low temperatures, where intermolecular forces become significant. Understanding real gases is crucial for accurately predicting the behavior of gases in practical applications.

5 Must Know Facts For Your Next Test

1. Real gases do not follow the ideal gas law at high pressures and low temperatures due to increased molecular interactions.
2. The behavior of real gases can be described using equations of state like the Van der Waals equation, which accounts for intermolecular forces and molecular volume.
3. Compressibility factors for real gases can indicate whether a gas behaves more like an ideal gas (Z ≈ 1) or if it shows significant deviations (Z < 1 or Z > 1).
4. Real gases can condense into liquids under certain conditions, unlike ideal gases which assume no phase changes occur.
5. Factors like molecular size and polarity affect how closely a real gas approaches ideal behavior.

Review Questions

• How do real gases differ from ideal gases in terms of behavior under different conditions?
  • Real gases differ from ideal gases primarily in their behavior under high pressures and low temperatures. While ideal gases follow the ideal gas law without deviations, real gases experience significant intermolecular forces that affect their pressure, volume, and temperature relationships. At high pressures, the finite volume occupied by gas molecules becomes important, while at low temperatures, attractions between molecules can lead to condensation, causing real gases to deviate from the predictions made by the ideal gas law.
• Discuss how the Van der Waals equation improves our understanding of real gas behavior compared to the ideal gas law.
  • The Van der Waals equation enhances our understanding of real gas behavior by incorporating corrections for molecular volume and intermolecular attractions. This equation modifies the ideal gas law by introducing two parameters: 'a', which accounts for attractive forces between molecules, and 'b', which corrects for the finite volume of gas molecules. By doing this, the Van der Waals equation provides a more accurate description of how real gases behave under various conditions, especially near their condensation points.
• Evaluate the significance of the compressibility factor in analyzing real gases and its implications for industrial applications.
  • The compressibility factor (Z) is significant in analyzing real gases because it quantifies how much a real gas deviates from ideal behavior. For industries relying on gaseous reactions or transport processes, understanding Z helps predict how gases will behave under varying temperatures and pressures, which is crucial for design and safety. In practical applications, deviations indicated by Z can influence equipment design, efficiency calculations, and even safety protocols when handling gases in storage or chemical processing.

Related terms

Ideal gas: An ideal gas is a hypothetical gas that perfectly follows the ideal gas law, where interactions between particles are negligible and the volume of particles is considered to be zero.

Van der Waals equation: The Van der Waals equation is an adjustment to the ideal gas law that accounts for the volume of gas molecules and the attractive forces between them, providing a more accurate description of real gas behavior.

Compressibility factor: The compressibility factor (Z) is a measure of how much a real gas deviates from ideal gas behavior, defined as the ratio of the molar volume of a real gas to the molar volume predicted by the ideal gas law.