Ideal Gases Flashcards
What is a mole?
The number of atoms in 12g of carbon-12, 16g of oxygen-16, etc.
What is Avogadro’s number?
6.02x10^23
What does the kinetic theory of gases describe?
The behaviour of atoms or molecules in an ideal gas.
What are the assumptions made for a gas to be ideal? (5 things)
- The gas contains a large number of molecules moving in random directions with random speeds.
- The molecules make up a negligible volume compared to the volume of the whole gas.
- Any collisions are perfectly elastic (no KE is lost).
- The length of time of collisions is negligible to the time between collisions.
- There are negligible forces between molecules except during collisions.
How does a gas create pressure in a container?
When a molecule bounces off the container walls, its momentum changes, meaning that it exerts a force on the wall. The total force from all the collisions divided by the area of the wall is equal to the pressure.
For an ideal gas of constant temperature, how is pressure related to volume?
Pressure is inversely proportional to volume. This is Boyle’s Law.
For an ideal gas of constant volume, how is pressure related to temperature?
Pressure is directly proportional to temperature. This is Charles’ Law.
For an ideal gas, how are pressure, volume and temperature related?
(pV)/T is a constant.
How can absolute 0 be estimated in a laboratory?
Measuring the variation of pressure with changes in temperature. A graph of pressure against temperature can then be extrapolated back to the point where pressure = 0. This should give a temperature value in Celsius for absolute 0.
What is the root mean squared speed of molecules in a gas?
The square root of the average squared speed of every molecule in the gas.
What is the Boltzmann constant (k)?
The molar gas constant (R) divided by the Avogadro Number (Na).
For an ideal gas, how is the molecular kinetic energy related to the absolute temperature?
Kinetic energy is directly proportional to the temperature.
