# Units, Constants, Conversions

Constants & Conversion Factors:

1 N = 1 kg m s-2                               1 Pa = 1 kg m-1 s-2 = N / m2

1 J = N m =1 kg m2 s-2                      1 bar » 1 atm

1 atm = 760 torr                               1 atm = 760 mm Hg

T(K)=T(oC)+273.15                         R = 0.08206 atm(L)/mol(K) = 8.3145 J mol-1 K-1

kB=1.38×10-23 J/K                            1 L atm = 101.34 J

1L = 1x10-3 m3                                 NA = 6.02214x1023

1 bar = 1x105 Pa                               1 cal = 4.184 J

F = 96485 C/mol                             c = 2.998×108 m/s

RT/F = 25.693 mV                          1 eV = 8065.5 cm-1

e = 2.71828                                     p = 3.14159

e = 1.6×10-19 C                                 h = 6.626×10-34 J s

eo = 8.854×10-12 C2/J m                    A = 0.509 (water, Debye-Huckel constant)

g = 9.8 m/s2                                     1 Amp = 1 A = 1 C/s (Coulomb per sec)

Mathematical Relationships:

ln x = ln 10 * log x » 2.3 log x

ln x + ln y = ln xy                              ln x – ln y = ln(x/y)

d ln x / dx = 1/x                                 d(f+g) = df + dg

d(fg) = fdg + gdf                               d(f/g) = 1/g df = f/g2 dg

Stirlings Approx:   ln N! = N ln N – N

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