What are units?

Units are standards for the measurement of physical quantities. We know Physical quantities are those properties of a substance that can be measured or observed without changing the identity or composition of the substance.

There are seven fundamental physical quantities:

Fundamental physical quantitiesS.I. unitSymbol
1. Lengthmeterm
2. Masskilogramkg
3. Timeseconds
4. TemperaturekelvinK
5. Amount of substancemolemol
6. Electric CurrentampereA
7. Luminous intensitycandelacd
Fundamental physical quantity

There are several other physical quantities that are derived from fundamental physical quantities and are known as “derived physical quantities”. For example Area, Volume, Pressure, etc.

Let us look at conversion of units of Physical quantities that are used frequently in Chemistry and Physics numerical problems.

This video covers the conversion of units of:

  • Length
  • Mass
  • Volume
  • Pressure

So, we have learned the conversion of units very well. Here are conversion tables listed for different units and their conversion:

Unit Conversion of Length
1 kilometer10^3 meters
1 centimeter10^{-2} meter
1 millimeter10^{-3} meter
1 micrometer10^{-6} meter
1 nanometer10^{-9} meter
1 angstrom10^{-10} meter
1 picometer10^{-12} meter
1 fermi10^{-15} meter
Unit Conversion of Mass
1 kilogram10^3 grams
1 milligram10^{-3} gram
Unit Conversion of Volume
1 kiloliter or 1 m^310^3 liters
1 milliliter or 1 cm^310^{-3} liter
Unit Conversion of Pressure
1 atmospheric pressure101325 pascal
1 atmospheric pressure760 mm of Hg
1 atmospheric pressure760 torr
1 atmospheric pressure1.013 bar

Leave a Reply

Your email address will not be published. Required fields are marked *