Deviations from Ideal Gas Law
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AP Chemistry › Deviations from Ideal Gas Law
Would you expect a polar or non polar gas to deviate most from ideal gas behavior?
Non polar gases, because of high dispersion interactions
Polar gases, because of high dipole-dipole interactions
Non polar gases because of reduced overall intermolecular forces
Polar gases because of hydrogen bonding
Both polar and non polar gases behave ideally
Explanation
Polar gases would have increased interactions due to their dipoles that would lead to deviations from ideal gas behavior.
When does a gas behave most like an ideal gas?
At low temperatures, low volume, low intermolecular interactions
At high temperatures, high volume, low intermolecular interactions
At low volumes, high temperatures, and high intermolecular interactions
At high temperature, high volumes, and high intermolecular interactions
At low temperatures, high volume, and low intermolecular interactions
Explanation
The ideal gas law assumes the gas particles are non-interacting and small relative to the size of their container. At high temperatures the gas molecules are moving fast enough to shorten the time scale for any interactions. At high volumes, the molecular size becomes small relative to the size of the container, and the low interactions mean the molecules act more independently.
Under which conditions would you expect Ar to deviate the most from ideal behavior?
200 K and 1 atm
200 K and 10 atm
300K and 5 atm
300K and 10 atm
Ar always behaves ideally
Explanation
The ideal gas law assumes the gas particles are non-interacting and small relative to the size of their container. At 200K (lowest temperature in the list, and the highest pressure). This gives Ar the most time to interact due to molecular speeds and the high pressure implies the molecular size is not insignificant relative to the container.
Which of the following would behave most like an ideal gas?
All are ideal gases because they are non-polar
Explanation
Why do gases deviate from ideal behavior as the temperature is decreased?
As the temperature is decreased the molecules have less kinetic energy and can’t maintain the intermolecular forces necessary for ideal gas behavior.
As the temperature is decreased the molecules have more kinetic energy and break the intermolecular interactions keeping them together.
As the temperatures is decreased the molecules become frozen in place.
As the temperature is decreased the molecules have less kinetic energy and can’t break the intermolecular interactions between them.
None of the above.
Explanation
The ideal gas law assumes the gas particles are non-interacting and small relative to the size of their container. As the temperature is decreased the gas molecules are moving slower and allow for a greater degree of interaction.