| prefix | symbol | factor × base unit |
| kilo | k | 103 |
| deci | d | 10–1 |
| centi | c | 10–2 |
| milli | m | 10–3 |
| micro | µ | 10–6 |
| nano | n | 10–9 |
| pico | p | 10–12 |
The SI (Systeme Internationale) system specifies a base unit each type of measurement. This unit is a standard quantity for that property, and all measurements of that property are relative to that standard. Three of the base units are shown below.
metre (m) for length
3 m is 3 times the standard length. 10 m is 10 times the standard length.
kilograms (kg) for mass
second (s) for time
These base units are related to smaller or larger units by factors that are powers of 10.
. Each factor has a symbol (like the k in kilogram).
Prefixes common used in chemistry are given in the table with their symbol and the factors by which they change the base unit.
Derived units:
Units can be multiplied and divided just like numbers. Therefore units for additional quantities can be derived from the base units above.
For example, the unit of volume can be derived from the unit of length because the volumes are equal to the product of three lengths. Recall that each of the units has an exponent of 1 even though that exponent is not shown, and that when multiplying exponential numbers to the same base, the exponents are added.