Discovering chemistry
Discovering chemistry

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Discovering chemistry

1.1 Units of volume

The SI unit of volume is the cubic metre (m3), but this is too large for the types of volumes laboratory chemists generally work with; litres, l (or cubic decimetres, dm3) are used instead, where 1 l = 1 dm3.

But what does 1 litre (or 1 dm3) of fluid look like? What about a millilitre (ml, one thousandth of a litre) or a microlitre (µl, one millionth of a litre)?

A litre is the volume of liquid (or gas) that would fit into a cube measuring 10 cm (or 1 dm) on each side: 10 cm × 10 cm × 10 cm = 1000 cubic centimetres (cm3) = 1 litre.

A millilitre is the volume of a cube measuring 1 cm on each side: 1 cm × 1 cm × 1 cm = 1 cm3 = 1 ml.

A microlitre is the volume of a cube measuring 1 mm on each side: 1 mm × 1 mm × 1 mm = 1 mm3 = 1 µl.

To help you visualise these volumes, consider the following:

A typical carton of fruit juice has a capacity of 1 litre.

A teaspoon holds about 5 ml of liquid.

One raindrop is about 30 µl.

  • Express 2 µl in litres.

  • 2 µl = 2 × 10−6 l


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