Physical and Chemical Constants, and Unit Conversion
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Table 4433. Physical and chemical constants, and unit conversion.

 Physical and chemical constants Comments a0 0.053 nm Bohr radius c = 2.99792 × 108 m/s The speed of light in vacuum P 1.01325 × 105 N/m2 Standard atmosphere 1 barn 10-24 cm2 1 Degree (°) 0.017453293 radian [rad] 1 k 1.38064852 × 10-23 J/K (or m2 kg s-2 K-1) (R/NAVO) Boltzmann constant 1 eV 1.60218 x 10-19 J = 23.053 kcal/mol 1 q 1.6021766208 x 10-19 C Elementary charge 1 kcal/mol 4.184 kJ/mol Or convert with excel file 1 kJ/mol 0.010364512 eV/bond Or convert with excel file 1 NAVO 6.02214086 × 1023 mol-1 Avogadro's constant 1 MeV/cm 1.602 x 10-11 J/m 1 Pa (pascal) 0.00001 bar = 1 x 10-5 bar Pa is in the SI system. 1 Pa (pascal ) 0.0075006375541921 Torr ≈ 7.5 x 10-3 Torr 1 Pa 1 newton/m2 1 mmHg (10-3mHg) 1 torr 1 m0 9.1095 × 10−31 kg, or 5.489×10−4 atomic mass units Electron rest mass 1 Mp 1.67264 × 10-27 kg Proton rest mass R 1.98719 cal mol-1K-1 Gas constant 1 radian [rad] 57.3 Degree (°) 1 angstrom (Å) 1 Å = 1 x 10-10 m = 1 x 10-4 µm 1 nm 1 x 10-9 m 1 oz 0.00625 lb 1 g 0.035274 oz 1 kT/q 0.0259 V Thermal voltage at 300 K 1,000 cm-1 0.124 eV ε0 8.854 × 10−12 farad/m = 8.85418 × 10−14 F/cm (1/µ0c2) Permittivity of of vacuum µ0 4π × 10−7 henry/m = 1.25663 × 10−8 H/cm (4π×10−9) Permeability of vacuum h 6.62617 x 10-23 ergs/sec = 6.62617 x 10-34 m2 kg/s = 6.62617 x 10-34 J-s Planck's constant hc 1239.84 eV nm h: Planck's constant; c: Speed of light. λ 1.23977 µm Wavelength of 1-eV quantum λ (nm) Wavelength of photons

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