Unformatted text preview: a spontaneous reaction to occur this is a good summary table showing effect of temperature, enthalpy and entropy on Gibbs free energy: Since Δ G is zero at a phase change we can also apply Gibbs free energy to phase changes and rearrange to give us the temperature of a phase change ΔH phase change Tphase change = ΔSphase change The applications for Gibbs free energy are very wide, and can be applied to many different systems and reactions. The following equations are the product of many derivations and €
calculations relating Gibbs free energy to other variables and conditions:  Under non standard conditions (because enthalpy is constant under changing pressure while entropy is not) [ products] = Q
⎛ྎ P ⎞ྏ
Reaction Quotient =
(G − G ) = RT ln⎜ྎ ⎟ྏ
[ reactants]
⎝ྎ P ( ΔG = RT ln (Q ) − RT ln⎠ྏ K ) can rearrange to get ΔG = RT ln (Q K ) Ethan Newton & Barry Zhang for SOS Winter 2012 €
30 ΔG = − RT ln (K ) REARRANGE TO GET $ −ΔG ' &
& RT )
) %
( *Don’t freak out because of all these equations. They are merely rearrangements of each other relating different variables. They have NOT been tested on in the past but do appear on your formula sheet if needed. K =e €
8.0 Practice Questions Gas Laws Questions 12.0g of liquid nitrogen is placed in an evacuated container and is allowed to boil. The pressure is later measured to be 50 kPa. How large was the container? (What if there was also 0.2 mol of oxygen in there?) Decreasing the ambient pressure can have negative effects on living organisms. The ultimate cause of these effects is that: a) the molecular speed of gas molecules increases b) by Boyle’s Law, the decrease in pressure also causes a decrease in the volume of oxygen in our tissues c) by Henry’s Law, less gas is able to dissolve in our blood d) the gases in our system are not ideal gases e) by the Ideal Gas Law, P has decreased while nRT has remained constant, so the volume of CO2 in our tissues increases In a parallel universe, the Universal Gas Constant is 16.62 kPa L K 1 mol  1. (All other parameters are the same). We would expect a) the average temperature of the universe to be higher b) Boyle’s Law to be invalid c) the Ideal Gas Law...
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 Winter '08
 carran
 Chemistry, Atom, Electron, Quantum Chemistry, Stoichiometry, Molecule, Chemical bond

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