important thermodynamic concepts Flashcards
1
Q
examples of bonding changes
A
can be covalent, ionic, noncovalent (pi stacking)
2
Q
internal energy
A
- U
- energy on atomic-molecular scale with changes in U related to changes in bonding and molecular motion
3
Q
enthalpy
A
- H
- easiest to understand in terms of change
4
Q
Enthalpy equation
A
ΔH = ΔU + PΔV
if ΔV is small, then ΔH is about equal to ΔU
5
Q
Entropy
A
- S
- measure of energetically equivalent places to randomly put energy (vibration, rotation, kinetic) with entropy’s change related to heat
6
Q
Gibbs free energy equation
A
Δ G = Δ H - TΔ S
7
Q
Negative Δ H
Negative Δ S
A
Low T = Δ G is negative
high T = Δ G is positive
8
Q
Negative Δ H
Positive Δ S
A
Low T = Δ G is negative
High T = Δ G is negative
9
Q
Positive Δ H
Negative Δ S
A
Low T = Δ G = positive
High T = Δ G is positive
10
Q
Positive Δ H
Positive Δ S
A
Low T = Δ G is positive
High T = Δ G is negative
11
Q
Free energy equation involving the biochemical standard state
A
ΔG = ΔG °’ + (RT) lnQ
12
Q
Q =
A
[Prod]^n / [React]^n
13
Q
Standard state equation
A
ΔG °’ = -(RT) lnK
K = equilibrium constant
14
Q
Chemical potential
A
- Contribution of particular substance to free energy of a system…
- plays a similar role for substances as electrical potential does for e-
- driving force
15
Q
How do homeostatic conditions differ from equilibrium?
A
- homeostasis needs energy to be stored, transferred and used. Equilibrium does not.
