Physical Constants
Conversion Factors
1 micron = 10
−6 m
1 nm = 10
−9 m
1 Å = 10
−10 m
1° =1/57.3 rad
1 eV = 1.602 Â 10
−19 J
1 erg = 10
−7 J
1 eV/entity = 96.49 kJ mol
−1 of (entities)
1 calorie = 4.18 J
1 atmosphere = 0.101325 MPa
1 torr (= 1 mm of Hg) = 133.3 Nm
−2
1 bar = 105 Nm
−2 = 10
−1 MPa
1 Psi = 6.90 kNm
−2
1 dyne/cm
2 = 0.1 Pa s
1 mol/cm
2 /sec = 10
4 mol m
−2 s
−1
1 mol/cm
3 = 10
6 mol m
−3
1 mol/cm
4 = 10
8 mol m
−4
1 cm
2 /sec = 10
−4 mol m
−2 s
−1
T° C = (T + 273.15) K
1 erg/cation = 1.43933 Â 10
13 kcal/mol
Avogadro’s number
N = 6.023 Â 10
23 mol
−1 = 6.023 Â 10
26 kmol
−1
Boltzmann’s constant
K = 1.380 Â 10
−23 JK
−1 = 8.614 Â 10
−5 eVK
−1
Gas constant
R = 8.314 Jmol
−1 K
−1
Planck’s constant
h = 6.626 Â 10
−34 Js = 6.626 Â 10
−27 ergs
Electronic charge
e = 1.602 Â 10
−19 C = 4.8 Â 10
10 esu
Electron rest mass
m 0 = 9.11 Â 10
−31 kg = 9.11 Â 10
−28 g
Proton rest mass
m p = 1.673 Â 10
−27 kg = 1.673 Â 10
−24 g
Neutron rest mass
M n = 1.675 Â 10
−27 kg = 1.675 Â 10
−24 g
Velocity of light
c = 3 Â 10
8 ms
−1 = 3 Â 10
10 cms
−1
Permitivity of free space
e 0 = 8.854 Â 10
−12 Fm
−1
Coulomb force constant
1/4p e 0 = 9 Â 10
9 Nm
2 C
−2
Atomic mass unit (amu)
(1/10
3
N) = 1.660 Â 10
−27 kg = 9.11 Â 10
−28 g
Acceleration due to gravity
g = 9.81 ms
−2
Ice point
0° C = 273.15 K
Units of Measurements
xi