A LevelPhysicsOCRRevision Notes5. Newtonian World & AstrophysicsKinetic Theory of GasesThe Boltzmann Constant

The Boltzmann Constant (OCR A Level Physics): Revision Note

Exam code: H556

Katie M

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Katie M

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The Boltzmann Constant

  • The Boltzmann constant k is used in the ideal gas equation and is defined by the equation:

The Boltzmann Constant equation 1

  • Where:

    • R = molar gas constant

    • NA = Avogadro’s constant

  • Boltzmann’s constant therefore has a value of

k equals fraction numerator 8.31 over denominator 6.02 cross times 10 to the power of 23 end fraction equals 1.38 cross times 10 to the power of negative 23 end exponent space straight J space straight K to the power of negative 1 end exponent

  • The Boltzmann constant relates the properties of microscopic particles (e.g. kinetic energy of gas molecules) to their macroscopic properties (e.g. temperature)

    • This is why the units are J K−1

  • Its value is very small because the increase in kinetic energy of a molecule is very small for every incremental increase in temperature

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Katie M

Author: Katie M

Expertise: Physics Content Creator

Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.

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