Chapter 31 Appendix G: Physical Constants and Conversion Factors

Selected Physical Constants
Atomic mass unit	1 amu = 1.6605389 × 10⁻²⁴ g
Atomic mass unit	1 g = 6.022142 × 10²³ amu
Avogadro’s number	N = 6.022142 × 10²³/mol
Boltzmann’s constant	k = 1.380651 × 10⁻²³ J/K
Charge on electron	e = 1.6021765 × 10⁻¹⁹ C
Faraday’s constant	F = 9.6485338 × 10⁴ C/mol
Gas constant	R = 0.0820575 (L atm)/(mol K)
Gas constant	= 8.31447 J/(mol K)
Mass of electron	m_e = 5.485799 × 10⁻⁴ amu
Mass of electron	= 9.109383 × 10⁻²⁸ g
Mass of neutron	m_n = 1.0086649 amu
Mass of neutron	= 1.6749273 × 10⁻²⁴ g
Mass of proton	m_p = 1.0072765 amu
Mass of proton	= 1.6726217 × 10⁻²⁴ g
Pi	π = 3.1415927
Planck’s constant	h = 6.626069 × 10 ⁻³⁴J s
Speed of light (in vacuum)	c = 2.99792458 × 10⁸ m/s (exact)

Useful Conversion Factors and Relationships
Length	Energy (derived)
Si unit: meter (m)	Si unit: joule (J)
$\begin{matrix} 1 km = 0. 62137 mi \\ 1 mi = 5280 ft \\ = 1.60 93 km \\ 1 m = 1 .0 936 yd \\ 1 in = 2 . 54 cm (exact) \\ 1 cm = 0. 39370 in . \\ 1 Å = 1 0^{- 10} m \end{matrix}$	$\begin{matrix} 1 J = 1 N ∙ m = 1 (kg ∙ m^{2}) / s^{2} \\ 1 J = 0. 2390 cal \\ = 1 V \times 1 C \\ 1 cal = 4 . 184 J (exact) \\ 1 eV = 1.602 \times 1 0^{- 19} J \end{matrix}$
Mass	Pressure (derived)
SI unit: kilogram (kg)	SI unit: pascal (Pa)
$\begin{matrix} 1 kg = 2.20 46 lb \\ 1 lb = 453 . 59 g \\ = 16 oz \end{matrix}$	$\begin{array}{l} 1 Pa = 1 N / m^{2} \\ = 1 kg / (m ∙ s^{2}) \\ 1 atm = 101,325 Pa \\ = 760 torr \\ = 14.70 lb / {in}^{2} \\ 1 bar = 1 0^{5} Pa \end{array}$
Temperature	Volume (derived)
Si unit: kelvin (K)	SI unit: cubic meter (m ³ )
$\begin{matrix} 0 K = - 273.15 ° C \\ = 459.67 ° F \\ K = ° C + 273.15 ° C \\ ° C = \frac{5}{9} (° F - 32 °) \\ ° F = \frac{9}{5} ° C + 32 \end{matrix}$	$\begin{matrix} 1 L = 1 0^{- 3} m^{3} \\ = {1 dm}^{3} \\ = 1 0^{3} {cm}^{3} \\ 1 gal = 4 qt \\ = 3 . 7854 L \\ {1 cm}^{3} = 1 mL \end{matrix}$