Here are some useful physical constants, conversion factors, and unit prefixes. They are used in many calculations in chemistry, as well as in physics and other sciences.
Useful Constants
| Acceleration of Gravity | 9.806 m/s2 |
| Avogadro’s Number | 6.022 x 1023 |
| Electronic Charge | 1.602 x 10-19 C |
| Faraday Constant | 9.6485 x 104 J/V |
| Gas Constant | 0.08206 L·atm/(mol·K)
8.314 J/(mol·K) 8.314 x 107 g·cm2/(s2·mol·K) |
| Planck’s Constant | 6.626 x 10-34 J·s |
| Speed of Light | 2.998 x 108 m/s |
| p | 3.14159 |
| e | 2.718 |
| ln x | 2.3026 log x |
| 2.3026 R | 19.14 J/(mol·K) |
| 2.3026 RT (at 25°C) | 5.708 kJ/mol |
Common Conversion Factors
| Quantity | SI Unit | Other Unit | Conversion Factor |
|---|---|---|---|
| Energy | joule | calorie erg | 1 cal = 4.184 J 1 erg = 10-7 J |
| Force | newton | dyne | 1 dyn = 10-5 N |
| Length | metre | Angstrom | 1 Å = 10-10 m = 10-8 cm = 10-1 nm |
| Mass | kilogram | pound | 1 lb = 0.453592 kg |
| Pressure | pascal | bar atmosphere mm Hg lb/in2 | 1 bar = 105 Pa 1 atm = 1.01325 x 105 Pa 1 mm Hg = 133.322 Pa 1 lb/in2 = 6894.8 Pa |
| Temperature | kelvin | Celsius Fahrenheit | 1°C = 1 K 1°F = 5/9 K |
| Volume | cubic metre | litre gallon (U.S.) gallon (U.K.) cubic inch | 1 L = 1 dm3 = 10-3 m3 1 gal (U.S.) = 3.7854 x 10-3 m3 1 gal (U.K.) = 4.5641 x 10-3 m3 1 in3 = 1.6387 x 10-6 m3 |
SI Unit Prefixes
| Factors | Prefix | Symbol |
|---|---|---|
| 1012 | tera | T |
| 199 | giga | G |
| 106 | mega | M |
| 103 | kilo | k |
| 102 | hecto | h |
| 101 | deca | da |
| 10-1 | deci | d |
| 10-2 | centi | c |
| 10-3 | milli | m |
| 10-6 | micro | µ |
| 10-9 | nano | n |
| 10-12 | pico | p |
| 10-15 | femto | f |
| 10-18 | atto | a |