| Constant | Value |
|---|---|
0.1 nm (exactly) |
|
Standard atmosphere (that is, 1 atm) |
101.3250 kPa (exactly) =1.013250 bar (exactly) = 760 torr (exactly) = 1.03323 kg(force) cm-2; Standard pressure is now defined as 100 kPa exactly. |
6.02214129 x 1023 mol-1 |
|
1.380 6488 x 10-23 J K-1 [934] |
|
Thermal energy (kT at 298 K) |
2.478 kJ mol-1 |
Celsius zero point (0°C exactly) |
273.15 K (exactly; a degree Celsius has the same size as one kelvin); Standard temperature is now defined as 273.15 K exactly. |
One nuclear disintegration per second (1 Curie (Ci) = 3.7x1010 Bq, exactly) |
|
3.33564095 x 10-30 C m (= -0.20819435 e- Å) |
|
e (base for natural logarithms) |
|
Electromagnetic radiation |
100 cm-1 = 109/nm = 1.197 KJ mol-1 ~ 3 THz |
Electron volt (eV) |
96.4853365 kJ mol-1 (Faraday = 96,485.3365 C mol-1) [934] |
Elementary charge (e) |
-1.602176565 x 10-19 C [934] |
Fahrenheit temperature scale (°F, obsolete) |
(Fahrenheit temperature) = (Kelvin temperature) × 9⁄5 − 459.67 (Kelvin temperature) = (Fahrenheit temperature + 459.67) × 5⁄9 |
Acceleration due to gravity (g, standard) |
9.80665 m s-2 (exactly) |
The golden
ratio (φ) |
1.618033988749894848204586834365638117720309179805... |
| Relative/absolute mass of 12C | 12 exactly / 1.660538921 x 10-27 kg |
| Meter | see speed of light below |
1012 s-1 (1 ps-1 |
|
The fraction 1/273.16 of the thermodynamic temperature of the triple point of water |
|
Kilocalorie (kcal, thermochemical) |
4.1840 kJ (exactly) |
8.3144621 J mol-1 K-1 [934] (= 0.08205746 L atm mol-1 K-1) |
|
| Molar volume of ideal gas 0°C, 100 kPa | 22.710953 x 10-3 m3 mol-1 |
Permeability of a vacuum (µ0) |
1.2566370614 µH m-1 (= 4π x 10-7 H m-1 exactly) |
8.854187817 pF m-1 (exactly)
[934] |
|
6.62606957 x 10-34 J s |
|
Π (=
circle circumference/diameter) |
|
2.99792458 x 108 m s-1 (exactly, also defines the meter)
[934] |
|
100 kPa, 273.15 K (exactly) |
|
Units |
micro- µ 10-6; nano- n 10-9; pico- p 10-12; femto- f 10-15; atto- a 10-18 kilo- k 103; mega- M 106; giga- G 109; tera- T 1012; peta- P 1015 |
Note that the SI unit definitions are under review for change soon; for example, the kelvin may be redefined in terms of an exactly defined value for the Boltzman constant and the kilogram may be defined in terms of its energy content [1031].
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This page was last updated by Martin Chaplin on 19 May, 2012
33.355640952 cm-1 = 299.792458 µm