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Chemistry LibreTexts

Units and Conversions

The International System of Units (SI) contains seven BASE UNITS that each represent a different kind of physical quantity.

  • SI unit: meter (m)
  • The meter defined as "the length of the path traveled by light in vacuum during a time interval of 1/299,792,458 of a second."
  • SI unit: cubic meter (\(m^3\))
  • The cubic meter is defined as the volume of a cube with edges one meter in length. A liter is exactly 1/1000th of a cubic meter.
  • SI unit: kilogram (kg)
  • The kilogram is defined as being equal to the mass of the International Prototype of the Kilogram (manufactured in 1799).
  • SI unit: pascal (Pa)
  • The pascal is a derived from other units

\[1\, Pa = 1 \dfrac{kg}{m \cdot s^2}\]

  • SI unit: kelvin (K)
  • The kelvin is defined as the fraction 1273.16 of the thermodynamic temperature of the triple point of water (exactly 0.01 °C).
  • SI unit: joule (J)
  • The joule is derived from other units

\[1 \, J = 1 \, kg \dfrac{m^2}{s^2}\]