User:Benjah-bmm27/degree/2/DMS

"Chemical Interactions": Web Book

Electrostatics

• Coulomb's law: $F={\frac {q_{1}q_{2}}{4\pi \epsilon _{0}r^{2}}}$
  • Permittivity $\epsilon$, vacuum permittivity $\epsilon _{0}$, relative permittivity $\epsilon _{R}$
  • $\epsilon =\epsilon _{0}\epsilon _{R}$
  • When in a medium other than vacuum, Coulomb's law becomes $F={\frac {q_{1}q_{2}}{4\pi \epsilon r^{2}}}$, that is $F={\frac {q_{1}q_{2}}{4\pi \epsilon _{0}\epsilon _{R}r^{2}}}$
• Lennard-Jones potential

Equations of state

• Ideal gas
• Perfect gas
• Van der Waals equation of state
  • reduced variables, e.g. reduced temperature and reduced pressure

Phase equilibria

• Gibbs' phase rule:

$\ F=C-P+2$

$\ C=N-R$

F: number of degrees of freedom of the system

P: number of phases present

C: number of independent components present

N: number of constituents present

R: number of constraints (e.g. constraint of mass balance)

• Phase equilibria
• Phase diagram
• Freezing-point depression
• Boiling-point elevation
• Triple point: temperature and pressure at which three phases of a substance (e.g. gas, liquid, and solid) coexist in thermodynamic equilibrium

For water, T_tp = 273.16 K

• Consolute point: on temp-comp phase diagrams, point at which distinction between co-existent phases vanishes - unlike a critical pt in that a phase change does occur
  • IUPAC definition, Wiktionary definition
• The mass of a molecule is not the reason for its volatility
• Lever rule

Properties of mixtures

• Distillation, including fractional distillation
• Raoult's law
• Henry's law
• Azeotropes
• Ethanol purification