Deviations from the ideal gas law are greater at Select one: a. high temperatures and low pressures. b. high temperatures and high pressures. c. low temperatures and low pressures. d. low temperatures and high pressures.
The Correct Answer and Explanation is:
The correct answer is d. low temperatures and high pressures.
Explanation:
The ideal gas law assumes that gases behave perfectly, meaning the gas molecules have no volume and do not interact with each other. However, real gases deviate from ideal behavior under certain conditions. These deviations are more pronounced under low temperatures and high pressures for the following reasons:
- At low temperatures:
- The kinetic energy of gas molecules decreases, causing the molecules to move more slowly.
- As a result, intermolecular forces, such as Van der Waals forces (attractive forces between molecules), become more significant. This contradicts the assumption of the ideal gas law, which assumes no intermolecular forces.
- As temperature decreases, molecules are more likely to interact, leading to deviations from the ideal gas law.
- At high pressures:
- At high pressures, gas molecules are forced closer together, and their volume becomes significant relative to the space between them. The ideal gas law assumes that the volume of gas molecules is negligible, but under high pressure, this assumption no longer holds true.
- Molecules are compressed into a smaller volume, which increases the frequency of molecular interactions and reduces the volume available for the gas, leading to deviations.
Why the other options are incorrect:
- a. High temperatures and low pressures: At high temperatures, gas molecules move faster, and the intermolecular forces have less of an effect. At low pressures, the volume of the gas molecules is insignificant, and their interactions are minimal. This leads to behavior close to the ideal gas law.
- b. High temperatures and high pressures: At high temperatures, the gas molecules move rapidly, reducing the influence of intermolecular forces. While high pressures can cause deviations, the high temperature helps to maintain ideal behavior by increasing molecular motion.
- c. Low temperatures and low pressures: Low temperatures do tend to cause deviations due to stronger intermolecular forces, but at low pressures, the volume of the gas molecules is still relatively small, so deviations are less significant.
In summary, low temperatures and high pressures lead to the greatest deviations from the ideal gas law due to the significance of intermolecular forces and the volume of gas molecules.
