Chapter 3- Thermodynamics Flashcards
First Law of Thermodynamics
Energy cannot be created or destroyed
Second Law of Thermodynamics
- The entropy of the universe increases
- The universe always tends toward increasing disorder or randomness
Enthalpy
Heat content of the reacting system
- Delta H= q
When heat energy is absorbed from the environment
Delta H> 0 = Endothermic reaction
When heat energy is released to the environment
Delta H< 0= exothermic reaction
The entropy of organized/ ordered systems is
Low ( Delta S > 0 when entropy increases)
Spontaneous
occurs without work
Non-spontaneous
brought about only by doing work (No natural tendency to occur)
Gibbs Free energy
Delta G = Delta H - T (Delta S)
Delta G < 0
Spontaneous/ exergonic
Delta G > 0
Non Spontaneous/ endergonic
Delta G= 0
Rxn at equilibrium
The more negative Delta G:
The more work the system can do
If Keq < 1
Reactants are favored
Keq > 1
Products are favored
Delta G ^o
-RTln(Keq)
The criterion of spontaneity of a reaction is the value of
Delta G
Bond energies indicate
how stable a compound is or how easy it is to break a particular bond
A larger bond energy means
it is harder to break and the compound is more stable
Does breaking a bond release energy?
NO
Can heat drive an isothermal chemical process?
NO
Net release of Free energy is when the
weakest bonds are broken in favor of the stronger bonds being formed
ATP’s energy results from products having a lower
free energy which makes the reactants more stable
How can endergonic biochemical reactions run against their thermodynamic potential?
coupling them to highly exergonic reactions
when combining multiple reactions, you combine the Delta G ^o values by
adding them
When combining multiple reactions, you combine the Keq values by
multiplying them
The hydrophobic effect is
an entropic effect
a decrease in entropy results in Delta S being
Negative
