• A barometer measures gas pressure by the height of the column of mercury.
  • One unit of gas pressure is the millimeter of mercury (mmHg).
  • An equivalent unit to the mmHg is called the torr.
  • Standard atmospheric pressure is called 1 atm of pressure and is equal to 760 mmHg and 101.3 kPa.
  • It is important to be able to convert between different units of pressure.
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