Thermodynamics

Question 1

Law of Mass Action

Answer 1

Keq = ([C]^c • [D]^c) / ([A]^a • [B]^b)

only if system is at equilibrium at a constant temp

equilibrium
kf[A]^2 = kr[B][C]

Question 2

reaction quotient

Answer 2

Qc = ([C]^c • [D]^c) / ([A]^a • [B]^b)
Q<Keq: not yet forward equilibrium
inc deltaG

Q>Keq: forward reaction has exceeded equilibrium
deltaG=0

Q=Keq: dynamic equilibrium
dec deltaG

Question 3

pure solids and liquids…

Answer 3

do not appear in keq expression

Question 4

keq vs equilibrium constant

Answer 4

keq ~> given temp

equilibrium constant ~> temp-dependent

Question 5

the larger the value of keq…

Answer 5

the farther right the equilibrium position

Question 6

if the forward rxn has a keq…

Answer 6

the reverse has a 1/keq

Question 7

change in P and V

Answer 7

only rxns w gases affected

Question 8

how does pressure inc affect the equilibrium state of a rxn containing a gas

Answer 8

• volume dec
• inc partial pressure of each gas in the system
• system will move towards whichever side has lower moles gas to dec pressure

Question 9

how does heat act in endo vs exothermic reactions

Answer 9

• endo deltaH>0, heat is a reactant
• exo deltaH<0, heat is a product

Question 10

kinetic product

Answer 10

lower temp fast
high free energy
less steric hindrance, easier to form
lack of stability

Question 11

thermodynamic product

Answer 11

higher temp slow
low free energy
steric hindrance