6.2.3

Ideal Gases

Test yourself

The Kelvin Scale

The Kelvin scale is a temperature scale that is commonly used in science.

Illustrative background for The Kelvin scale Illustrative background for The Kelvin scale  ?? "content

The Kelvin scale

  • The Kelvin scale is an absolute temperature scale defined to have 0 K at the lowest possible temperature, called absolute zero.
Illustrative background for Absolute zeroIllustrative background for Absolute zero ?? "content

Absolute zero

  • Absolute zero (0 K) is the lowest possible temperature.
  • At absolute zero, there is no temperature.
    • This means that there is no kinetic energy or vibration of molecules.
Illustrative background for Converting from degrees Celsius to KelvinIllustrative background for Converting from degrees Celsius to Kelvin ?? "content

Converting from degrees Celsius to Kelvin

  • To find degrees Celsius from Kelvin, just add 273.15.
    • E.g. 0oC = 273.15 K.
    • E.g. Water boils at 373.15 K.

Ideal Gas Law

The ideal gas law is a good model for the behaviours of large amounts of gas.

Illustrative background for Ideal gas lawIllustrative background for Ideal gas law ?? "content

Ideal gas law

  • The ideal gas law can be written as:
    • Pressure x volume = number of moles x ideal gas constant x temperature
    • pV=nRT
      • Where R is the ideal gas constant and has a value of 8.31
  • This equation can be rearranged to solve for any of the terms.
Illustrative background for Boltzmann constant Illustrative background for Boltzmann constant  ?? "content

Boltzmann constant

  • Ideal gas constant x number of moles = Boltzmann constant x number of molecules
    • Rn=kNRn=kN
Illustrative background for Avogadro's number Illustrative background for Avogadro's number  ?? "content

Avogadro's number

  • This equation gives the relationship between the ideal gas constant, the Boltzmann constant and Avogadro's number (the number of molecules in a mole):
    • Na=R/kN{_a}=R/k
  • Using the ideal gas law and the above equation, we can now write:
    • pV=NkTpV=NkT

Jump to other topics

1Measurements & Errors

2Particles & Radiation

3Waves

4Mechanics & Materials

5Electricity

6Further Mechanics & Thermal Physics (A2 only)

7Fields & Their Consequences (A2 only)

8Nuclear Physics (A2 only)

9Option: Astrophysics (A2 only)

10Option: Medical Physics (A2 only)

11Option: Engineering Physics (A2 only)

12Option: Turning Points in Physics (A2 only)

Go student ad image

Unlock your full potential with GoStudent tutoring

  • Affordable 1:1 tutoring from the comfort of your home

  • Tutors are matched to your specific learning needs

  • 30+ school subjects covered

Book a free trial lesson