Unfortunately, I don't think there's a website that's assembled all the important ones for VCE Chemistry. So here's my mini-guide! =)

Firstly, make sure you're aware of the basic prefixes (provided in the data book) and how to use them:

Prefix   10n

giga     109
mega     106
kilo     103
(none)   1
deci     10-1 (this one is unusual because it's not in the 3, 6, 9 pattern)
centi    10-2 (this one is unusual because it's not in the 3, 6, 9 pattern)
milli    10-3
micro    10-6
nano     10-9

Make sure to remember to apply the unit's powers to the prefix too.

For example: 10 dm³ = 10 x (10^-1)³ m³ = 0.01 m³

Volume

It can be measured as distance cubed (e.g.: cm³ or m³) or under litres (mL or L).

Conversions between the two:

• 1 mL = 1 cm³
• 1 L = 1 dm³ (or 1 L = 1000 mL = 1000 cm³)

In VCE, volume is preferably expressed as litres (L)

Pressure

It can be measured in Pascals (Pa or kPa, preferred), or atmospheres (atm) or mmHg.

The conversion rule is: 760 mmHg = 1 atm = 101.3 kPa

In VCE, pressure is preferably expressed as kilopascals (kPa)

Density

This is not really a unit conversion, but if you know the density of something, for example: 1.2 g/mL, then you can convert something like 100 mL into 120 g.

An important fact to know is that the density of water is 1 g/mL, hence you can interconvert grams and millilitres for water!

Concentration

There are lots of ways to measure concentration. The odd ones to work out are:

• ppm
• ppb

On a mass basis (w/w or m/m), 1 ppm = 1 g per million grams and 1 ppb = 1 g per billion grams.

The key with concentrations is to work with the units. There is no point remembering how each one goes.