Physical Constants and Tables




Physical Constants

Constant
Symbol
Value
Avogadro's number N 6.02214 x 1023 mol-1
Boltzmann constant k 1.38066 10-23 J/K
Faraday's constant F 96.485 kJ/volt
96,485 C/mol
Gas constant R 8.31451 J/K mol
0.08206 L atm/K mol
Planck's constant h 6.62608 x 10-34 J s
Speed of light c 2.99792458 x 108 m/s



SI Prefixes for Units

Prefix Symbol 10n Decimal Short scale Long scale
yotta Y 1024 1000000000000000000000000 Septillion Quadrillion
zetta Z 1021 1000000000000000000000 SextillionTrilliard
exa E 1018 1000000000000000000 Quintillion Trillion
peta P 1015 1000000000000000 Quadrillion Billiard
tera T 1012 1000000000000 Trillion Billion
giga G 109 1000000000 Billion Milliard
mega M 106 1000000 Million
kilo k 103 1000 Thousand
hecto h 102 100 Hundred
deca da 101 10 Ten
100 1 One
deci d 10-1 0.1 Tenth
centi c 10-2 0.01 Hundredth
milli m 10-3 0.001 Thousandth
micro 10-6 0.000001 Millionth
nano n 10-9 0.000000001 Billionth Milliardth
pico p 10-12 0.000000000001 Trillionth Billionth
femto f 10-15 0.000000000000001 Quadrillionth Billiardth
atto a 10-18 0.000000000000000001 Quintillionth Trillionth
zepto z 10-21 0.000000000000000000001 Sextillionth Trilliardth
yocto y 10-24 0.000000000000000000000001 Septillionth Quadrillionth



Conversion Factors

work: joule
J
work done by accelerating 1 g at 1 cm/sec2 for 1 m 1 J = 9.869 x 10-3 L atm 1000 J = 1 kJ
1018 J = 1 EJ (exajoule)
mass/energy Joule
J
energy in mass units (for E=mc2) 1 J = 1 kg m-2 s-2
work electron volt
eV
energy to accelerate 1 electron by 1 volt of potential difference 1 eV = 1.1602 x 10-19 J
heat: calorie
cal
heat needed to raise the temperature of 1 g of H2O by 1 deg C 1 cal = 4.184 J
1000 cal= 1 kcal
heat: British thermal unit
BTU
heat needed to raise the temperature of 1 lb of H2O by 1 deg F 1 BTU = 1.055 kJ
power: watt
W
rate at which the energy, in joules, is delivered 1 W = 1 J/sec
1000 W = 1 kW
other kilowatt hours
kWh
1 kilowatt delivered over 1 hour 1 kWh = 3.6 x 106 J
other wavenumber
cm-1
1/wavelength of electromagnetic radiation 1 cm-1 = 0.01196 kJ/mol
other Hertz
s-1, Hz
frequency of electromagnetic radiation 1 s-1 = 3.99 x 10-13 kJ/mol
mass atomic mass unit
amu
mass of proton 1.6605 x 10-27 kg
pressure atmosphere
atm
atmospheric pressure at sea level 101.325 kilopascals
760 torr (mm Hg)
14.7 psi
1.01325 bar


Temperature:
  1. Farenheit
      Water freezes at 32 deg F and boils at 212 deg F (at 1 atm).

  2. Celsius or centigrade
      Water freezes at 0 deg C and boils at 100 deg C (at 1 atm).
      (Tdeg C x 9/5) + 32 = Tdeg F

  3. Kelvin
      This is the absolute scale. At 0 K, molecular motion is zero. TK = Tdeg C + 273.15



Periodic Table

See also Web Elements for information about individual elements.


Ionization Energies
Electron configuration Ionization Reaction Energy Required
[He]2s1 Li Li+ + e- 520 kJ/mol
[He]2s2 Be Be+ + e- 899 kJ/mol
[He]2s22p1 B B+ + e- 800 kJ/mol
[He]2s22p2 C C+ + e- 1090 kJ/mol
[He]2s22p3 N N+ + e- 1400 kJ/mol
[He]2s22p4 O O+ + e- 1310 kJ/mol
[He]2s22p5 F F+ + e- 1680 kJ/mol
[He]2s22p6 Ne Ne+ + e- 2080 kJ/mol



Atomic Orbital Ionization Energies



Electronegativity and Electron Affinity

The electron affinity is the heat released (negative energy term) when a free electron combines with a neutral atom to make a negatively charged ion.
F + e- F- -328 kJ/mol
Cl + e- Cl- -349 kJ/mol
Br + e- Br- -324 kJ/mol
I + e- I- -295 kJ/mol

Here is a periodic table that includes the electron affinities. Note that the numbers are in kJ of energy released and should be negative numbers. By convention, energy added to a system has a positive value and energy released from a system has a negative value.



Electronegativity is a property of atoms within molecules rather than free atoms. It measures the tendency of that atom to draw bonding electrons towards itself.



Bond Dissociation Energies

O2 498 kJ/mol
O3 364 kJ/mol
HO-OH 142 kJ/mol
HO-H 459 kJ/mol
H3C-H 435 kJ/mol
ON-O 300 kJ/mol
O2N-O 190 kJ/mol
Cl-Cl 253 kJ/mol
H2N-NH2 160 kJ/mol
N2 941 kJ/mol



Average Bond Energies

molecule
kJ/mol
molecule
kJ/mol
molecule
kJ/mol
molecule
kJ/mol
H—F
565
N—N
160
I—Cl
208
C ≡ C
839
H—Cl
427
N—F
272
I—Br
175
O = O
495
H—Br
363
N—Cl
200
C=O in CO2
799
C = O
745
H—I
295
N—Br
243
S—H
347
C ≡ O
1072
 
 
N—O
201
S—F
327
N = O
607
C—H
413
O—H
467
S—Cl
253
N = N
418
C—C
347
O—O
146
S—Br
218
N ≡ N
941
C—N
305
O—F
190
S—S
266
C ≡ N
891
C—O
358
O—Cl
203
 
 
C = N
615
C—F
485
O—I
234
Si—Si
340
C=C
614
C—Cl
339
Si—H
393
 
 
 
C—Br
276
F—F
154
Si—C
360
 
 
C—I
240
F—Cl
253
Si—O
452
 
 
C—S
259
F—Br
237
 
 
 
 
 
 
Cl—Cl
239
 
 
 
 
 
 
Cl—Br
218
 
 
 
 
 
 
Br—Br
193
 
 
 
 



Enthalpies of Formation

molecule
kJ/mol
molecule
kJ/mol
molecule
kJ/mol
O 249.17 O3 142.7 H2O(g) -241.82
H2O(l) -286 H2O2(l) -187.78 H 217.97
N 472.70 NO(g) 90.25 N2O(g) 82.05
NO2(g) 33.18 NO3(g) 78.9 HNO3(g) -124.2
SO2(g) -296.83 SO3(g) -395.72 H2SO4 -719
H2S(g) -20.63 SF4(g) -753.0 SF6(g) -1209
Cl 121.68 HCl(g) -92.31 HOCl -71.5
ClO2(g) 99.0
C(g) 716.68 CO(g) -110.53 CO2(g) -393.51
CH4 -78.81 CH3 145.69 C2H6 -84.68
C2H4 52.26 C2H2 226.73 C3H8 -82.4
C3H6 52.3 C4H10 -126.5 1-butene
C4H8
20.4
butadiene
C4H6
175.8 C5H12 -114.9 C6H14 -130.1
CH3OH -190.1 CH3CH2OH -217.1 CH2O -104.9
glucose
C6H12O6
-1271 sucrose
C12H22O11
-2226 ribose
C5H10O5
-1051
arabinose
C5H10O5
-1058



Acid Dissociation Constants

For all acids (HA) listed here, the dissociation reaction is:

HA + H2O H+(aq) + A-(aq) Ka = [H+(aq)] [A-(aq)]/ [HA] pKa = -log Ka


Name Formula pKa
Perchloric acid HClO4 -10
Hydroiodic acid HI -10
Hydrobromic acid HBr -9
Hydrochloric acid HCl -7
Hydrofluoric HF 3.17
Sulfuric acid H2SO4 -3
Bisulfate ion HSO3- 1.99
Nitric acid HNO3 -1.5
Trifluoroacetic acid CF3C(O)OH 0.5
Fluoroacetic acid CFH2C(O)H 2.6
Trichloroacetic acid CCl3C(O)OH 0.77
Dichloroacetic acid CCl2HC(O)OH 1.25
Chloroacetic acid CClH2C(O)OH 2.86
Benzoic acid PhC(O)OH 4.2
Formic acid HC(O)OH 3.75
Acetic acid CH3C(O)OH 4.8
Phenol PhOH 10.0
Water H2O 15.7
Hydronium H3O+ -1.7
Methanol CH3OH 15.5
Ethanol CH3CH2OH 15.9
1-methylethanol (CH3)2CHOH 17.1
1,1-dimethylethanol (CH3)3COH 18
Hydrogen sulfide H2S 7.0
Ammonium NH4+ 9.24
Ammonia NH3 38
Protonated acetone (CH3)2C=O-H+ -7
Carbonic acid H2CO3 3.6
Bicarbonate ion HCO3- 10.3


Acid Dissociation Constants for Polyprotic Acids
Acid Name    K pKa
Carbonic, H2CO 1st 4.5 x 10-7  6.35*

2nd 4.7 x 10-11 10.33 
Hydrogen sulfide, H2 1st 9.5 x 10-8 7.02

2nd 1.0 x 10-19 19.0
Phosphoric acid, H3PO 1st  7.1 x 10-3  2.15

2nd  6.3 x 10-8 7.20

3rd  4.5 x 10-13  12.35 
Sulfuric acid, H2SO 1st  large

2nd 1.2 x 10-2  1.92
Telluric acid, H6TeO6 1st  2.0 x 10-8  7.7

2nd  1.0 x 10-11 11.0

3rd  3.0 x 10-15 14.5
Sulfurous acid, H2SO3 1st  1.2 x 10-2  1.92

2nd 6.6 x 10-8 7.18
Selenous acid, H2SeO3 1st  3.5 x 10-3  2.46

2nd  5.0 x 10-8  7.3
Tellurous acid, H2TeO3 1st  3.0 x 10-3  2.5

2nd  2.0 x 10-8  7.7
Ascorbic acid, H2C6H6O 1st 7.9 x 10-5 4.10

2nd  1.6 x 10-12 11.79
Citric acid, H3C6H5O7 1st  7.1 x 10-4  3.15

2nd 1.7 x 10-5 4.77

3rd  6.4 x 10-6  5.19

* Includes the hydration equilibrium between CO2(aq) and H2CO3.


Gas Solubility Constants




Solubility Product Constants
Mineral Equation Ksp
calcium carbonate CaCO3 Ca+2 + CO32- 3.8 x 10-9
calcium hydroxide Ca(OH)2 Ca+2 + 2 HO- 5.0 x 10-6
calcium phosphate Ca3(PO4)2 3 Ca+2 + 2 PO43- 1 x 10-26
hydroxyapatite Ca5(PO4)3(OH) 5 Ca+2 + 3 PO43- + HO- 1 x 10-36
fluoroapatite Ca5(PO4)3F 5 Ca+2 + 3 PO43- + F- 1 x 10-60
aluminum hydroxide Al(OH)3 Al3+ + 3 HO- 3 x 10-34
aluminum phosphate AlPO4 Al3+ + PO43- 9.8 x 10-21
iron(II) carbonate FeCO3 Fe+2 + CO3-2 3.1 x 10-11
iron(II) sulfide FeS Fe+2 + S-2 8 x 10-19



Specific Heat

For any pure substance, there is a specific quantity of heat energy required to increase the temperature of 1 gram of the substance by 1 degree. This is called the specific heat or heat capacity.

q = m x C x T

Specific Heat at 25 deg C
substance C (J g-1 deg-1)
air 1.01
copper 0.385
ethanol 2.44
hydrogen 14.3
silica 0.703
water 4.18




Standard reduction half cell potentials

Reductio Reaction Potential, V
F2 + 2 e- 2 F- 2.87
Co+3 + e- Co+2 1.82
H2O2 + 2 H+ + 2 e- 2 H2O 1.78
PbO2 + 4 H+ + SO42- + 2 e- PbSO4 + 2 H2O 1.69
MnO4- + 4 H+ + 3 e- MnO2 + 2 H2O 1.68
PbO2 + 4 H+ + 2 e- Pb+2 + 2 H2O 1.46
Cl2 + 2 e- 2 Cl- 1.36
Cr2O72- + 14 H+ + 6 e- 2 Cr+3 + 7 H2O 1.33
O2 + 4 H+ + 4 e- 2 H2O 1.23
Ag+ + e- Ag 0.800
Fe+3 + e- Fe+2 0.77
I2 + 2 e- 2 I- 0.54
Cu+ + e- Cu 0.52
Cu+2 + e- Cu+ 0.16
gluconic acid + 2 H+ + 2 e- glucose + H2O 0.050
[Fe(CN)6]3- + e- [Fe(CN)6]4- 0.436
2 H+ + 2 e- H2 0.000
Pb+2 + 2 e- Pb -0.13
Ni+2 + 2 e- Ni -0.23
PbSO4 + 2 e- Pb + SO42- -0.35
H2O + e- 1/2 H2 + OH- -0.415
Zn+2 + 2 e- Zn -0.76
CO2 + e- CO2- -1.84
Na+ + e- Na -2.71
Li+ + e- Li -3.04



Log Table






Professor Patricia Shapley, University of Illinois, 2011