Question

Explain why the plot of PV for CO₂ differs from that of an ideal gas.

a) CO₂ molecules have a different shape compared to ideal gas molecules.
b) CO₂ exhibits strong intermolecular forces not present in ideal gases.
c) CO₂ has a higher molar mass compared to ideal gases.
d) CO₂ is at a higher temperature compared to ideal gases.

Answer 1

The plot of PV for CO₂ differs from that of an ideal gas because CO₂ exhibits significant intermolecular forces and molecules with non-negligible volume, causing deviations from ideal gas behavior at high pressures and low temperatures.

Step-by-step explanation:

The plot of PV (pressure-volume product) for CO₂ (carbon dioxide) differs from that of an ideal gas primarily due to intermolecular forces. Unlike ideal gases, real gases such as CO₂ have molecules with nonzero volumes and experience intermolecular attractions.

Deviations from ideal gas behavior are significant at high pressures and low temperatures, where these factors can no longer be ignored. For CO₂, the attractive forces are the predominant aspect affecting deviations at low pressures, leading to lower PV/nRT values than predicted.

Conversely, at high pressures, the non-negligible volume of CO₂ molecules becomes significant, resulting in higher PV/nRT values than predicted by the ideal gas law.

These deviations from the ideal gas law can be explained using the van der Waals equation, which includes corrections for gas molecule volume and intermolecular forces.

These corrections are significant because, in reality, gas molecules occupy space (unlike the point particles in an ideal gas) and interact with each other via dispersion forces, which are related to molecular mass and size.

Therefore, CO₂’s plot of PV differs from that of an ideal gas because it exhibits both non-negligible molecular volume and intermolecular forces.