General Chemistry/Units
< General Chemistry
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".