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/s^{2} |

Avogadro’s Number | 6.022 x 10^{23} |

Electronic Charge | 1.602 x 10^{-19} C |

Faraday Constant | 9.6485 x 10^{4} J/V |

Gas Constant | 0.08206 L·atm/(mol·K) 8.314 J/(mol·K) 8.314 x 10 |

Planck’s Constant | 6.626 x 10^{-34} J·s |

Speed of Light | 2.998 x 10^{8} 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/in ^{2} | 1 bar = 10^{5} Pa1 atm = 1.01325 x 10 ^{5} Pa1 mm Hg = 133.322 Pa 1 lb/in ^{2} = 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 dm^{3} = 10^{-3} m^{3}1 gal (U.S.) = 3.7854 x 10 ^{-3} m^{3}1 gal (U.K.) = 4.5641 x 10 ^{-3} m^{3}1 in ^{3} = 1.6387 x 10^{-6} m^{3} |

**SI Unit Prefixes**

Factors | Prefix | Symbol |
---|---|---|

10^{12} | tera | T |

19^{9} | giga | G |

10^{6} | mega | M |

10^{3} | kilo | k |

10^{2} | hecto | h |

10^{1} | 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 |