Thermodynamics (Dr.Miles TAMU) Flashcards
Isolated systems
No exchange of energy or matter (thermos)
Closed system
Only energy allowed to exchange (unopened soda)
- Matter inside system will always stay
- If System is heated then gaining energy, if cooled then losing energy
Open system
Both energy and matter allowed to exchange. (humans, cell)
- all living things are open systems
How to change internal energy for a closed system
Heat or work
If any energy is added or lost it comes from and goes to
The surroundings and the amount of energy in the universe is constant (1st law of thermodynamics)
+q vs -q
positive means heat is being added to the system from surroundings and negative means system is losing energy to the surroundings
+w vs -w
positive work is done by the system(loses energy) on the surrounding and negative work means that the surrounding is doing work on the system (gains energy)
State functions
Energy = state of system and the pathway the system took took t reach the state
- E is independent of the path
- Always represented by a capital number
Non state functions
Dependent n the pathway used to go from initial to final state
- Will always be represented by lower case letter
Enthalpy
defined as: H = E + PV
- q put in doesn’t remain as heat but can be work passed into the surroundings
- ΔH = ΔE + ΔPV
If ΔH is more than 0(positive)
then heat energy is being put into the system. Such a condition is termed endothermic
If (Δ)H is less than 0(negative)
then heat energy is given off by the system. Such a condition is termed exothermic
entropy
Increase in Randomness and disorder
2nd Law of Thermodynamic
All spontaneous processes proceed from an ordered to disordered state. All spontaneous processes increase the entropy of the universe. All spontaneous reactions will proceed till equilibrium is reached.
The sign of (Δ)G determines _____and the magnitude of ΔG indicates_____
Direction, how far the process proceeds to equilibrium
Equilibrium
Is a state of minimum potential energy
- any process with a nonzero ΔG will spontaneously proceed to equilibrium
if the process A to B is associated with free energy, then how will the reaction proceed in ΔG is positive? Negative?
- If ΔG is positive then the process will proceed in the reverse direction. i.e. B to A
- If ΔG is negative then the process will proceed as written. i.e. A to B
All living things are entropy ____ at the expense of universe and/or surroundings. Living organism are always battling ____
catalyst(speed up), entropy
Gibbs free energy equation
ΔG=ΔH-TΔS
When the reaction has a negative ΔH and a Positive ΔS, what is the reaction type? is it endergonic or exergonic at T? is it always spontaneous?
G<0
~ This is an exothermic reaction because G<0
~ process is exergonic at all temperatures
~ spontaneous all temperatures
~ and is at equilibrium when G=0
When the reaction has a negative ΔH and a negative ΔS, what is the reaction type? is it endergonic or exergonic at T? is it always spontaneous? what are the opposed and driven
~ This is an exothermic reaction
~ when T>H/S its endergonic
~ when T<H/S its exergonic
~ Spontaneous as some temperatures
~ Entropically opposed, enthalpically driven
When the reaction has a positive ΔH and a positive ΔS, what is the reaction type? is it endergonic or exergonic at T? is it always spontaneous? What are the opposed and driven
~ This is an endothermic reaction
~ when T<H/S is it Endergonic
~ when T>H/S it is exergonic
~ Spontaneous at some temps
~ Entropically driven, enthalpically opposed
When the reaction has a positive ΔH and a negative ΔS, what is the reaction type? is it endergonic or exergonic at T? is it always spontaneous
G>0
~ The reactions is endothermic because G>0
~ process is endergonic is at all temperatures
~ nonspontaneous at all temperatures
~ is at equilibrium when G=0
R gas constant =
8.3145 J/mol*K
equilibrium constant formula given ΔG0
ΔG=-RTln(Keq)
