General Chemistry/Units

SI Fundamental Units

These are the seven basic SI units from which all other units are constructed.

Quantity	Symbol	Unit	Unit Symbol
Length	l	metre/meter	m
Time	t	second	s
Mass	m	kilogram	kg
Thermodynamic temperature	T	kelvin	K
Amount of substance	n	mole	mol
Electrical charge	Q	coulomb	C
Luminous intensity	IV	candela	cd

SI Derived Units

All other units are derived units. They are built from fundamental units. This is a small selection of units that may be found in General Chemistry.

Quantity	Symbol	Unit	Unit Symbol	Derived From
Force	F	newton	N	kg·m·s-2
Energy	U	joule	J	kg·m2·s-2
Pressure	P	pascal	Pa	kg·m-1·s-2
Power		watt	W	kg·m2·s-3
Electrical current	I	ampere	A	C·s-1
Electrical potential	V	volt	V	J·C-1

SI Prefixes

A prefix appears before a unit's symbol when expressing very large or very small quantities. For example: 0.001 kg = 1 g = 1000 mg.

1000n	10n	Prefix	Symbol	Decimal
10008	1024	yotta	Y	1 000 000 000 000 000 000 000 000
10007	1021	zetta	Z	1 000 000 000 000 000 000 000
10006	1018	exa	E	1 000 000 000 000 000 000
10005	1015	peta	P	1 000 000 000 000 000
10004	1012	tera	T	1 000 000 000 000
10003	109	giga	G	1 000 000 000
10002	106	mega	M	1 000 000
10001	103	kilo	k	1 000
	102	hecto	h	100
	101	deca	da	10
10000	100	(none)	(none)	1
	10−1	deci	d	0.1
	10−2	centi	c	0.01
1000−1	10−3	milli	m	0.001
1000−2	10−6	micro	µ	0.000 001
1000−3	10−9	nano	n	0.000 000 001
1000−4	10−12	pico	p	0.000 000 000 001
1000−5	10−15	femto	f	0.000 000 000 000 001
1000−6	10−18	atto	a	0.000 000 000 000 000 001
1000−7	10−21	zepto	z	0.000 000 000 000 000 000 001
1000−8	10−24	yocto	y	0.000 000 000 000 000 000 000 001

Solution Concentration Units

Quantity	Symbol	Units	Description
Molarity	M	mol/L	moles of solute per liter of solution
Molality	m	mol/kg	moles of solute per kilogram of solvent
Mole Fraction	χ	(none)	moles of solute per moles of solution
Parts per million	ppm	(none)	milligrams of solute per kilogram of solution
Parts per billion	ppb	(none)	micrograms of solute per kilogram of solution

Other Useful Units

Volume

Volume Unit	Conversion	Mass of Water (4 °C)
1 L	= 1000 cm3	1 kg
1 cm3	= 1 mL	1 g
1 m3	= 1000 L	1000 kg

Pressure

Name	Symbol	Conversion
Atmosphere	atm	= 760 torr	= 101.325 kPa
Pascal	Pa	≈ 7.5 x 10-3 torr
Torr (mm Hg)	torr	≈ 133.3 Pa
Pound-per-square inch	psi	≈ 51.7 torr	≈ 6.894 kPa

Temperature

One degree Celsius is equal to one Kelvin (in magnitude).

Name	Symbol	Abs. Zero	M.P. of Water	B.P. of Water
Fahrenheit	°F	-456.67 °F	32 °F	212 °F
Celsius	°C	-273.15 °C	0 °C	100 °C
Kelvin	K	0 K	273.15 K	373.15 K

* Notice it is not "degrees Kelvin".