C3261 Final Flashcards
In any gas, molecules obey which distribution?
Maxell-Boltzmann Distribution
What is the most probable velocity?
The apex velocity, vp
What is the equation of the most probable velocity, vp?
vp=sqrt(2RT/M)
As the size of a gas molecule increases, what happens to the average velocity?
Decreases
What equation is mainly used to describe a real gas? (do not need to give the equation just the name)
Van der Waals equation
Triple point
all 3 phases are in equilibrium
Vapour Pressure
Below the boiling point, some molecules have enough E to escape the surface as a gas
At what point is the boiling point in terms of vapour P?
Boiling point when vapour P=external P
What do melting and boiling points largely depend on?
Intermolecular forces
Clathrate
A host-guest combination when molecules are trapped in interstitial spaces of an ice structure
Hydrate clathrate
A specific clathrate in which the host is ice
What happens when a clathrate-hydrate melts?
Guest is released as there is no bond between the host and guest
What is the packing arrangement of hydrate clathrates and what are the 2 types of cages in the structure?
Weaire-Phelan geometry
1. 2 cages with pentagonal faces
2. 6 cages with hexagonal faces
What do thermodynamics describe in a reaction?
If a reaction happens or not
What do kinetics describe in a reaction?
How fast the reaction will be
Gibb’s Free Energy equation
dG=dH-TdS
Order of entropy for states
s<l<g
With an increase in gas molecules, what happens to the entropy?
Increases
Photochemically-Driven Rxns
driven by photon energy during the daytime; highest E radiation in Earth’s upper atmosphere
What are the photochemical E relations? (2)
E=Nhv
N=avogadros number
h=Planck’s constant
v=frequency of EM radiation
c=lambda v
Ionization reactions
Occur in upper atmosphere and solar system
Ionization Energy
Minimum E required to ionize a molecule or atom
Electron Affinity
E required for addition of electrons to an atom or molecule
Hund’s First rule
The ground state has the greatest multiplicity, i.e. the highest number of unpaired electrons