Thermodynamics Flashcards

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1
Q

Avogadro’s Law

A

under the same conditions of temperature and pressure, equal volumes of different gases contain an equal number of molecules

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2
Q

Charles’s Law

A

experimental gas law that describes how gases tend to expand when heated

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3
Q

Heat

A

Thermal motion

Temperature is a way to compare heat energy between objects

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4
Q

Statistical view of temperature

A

Average kinetic energy is proportional to temperature

- Maxwell Boltzmann curve

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5
Q

Boyle’s Law

A

The absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system

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6
Q

Ideal Gas Law

A
PV = nRT
R = 8.314 J/mol x K
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7
Q

Work as a form of energy

A

force x distance

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8
Q

Heat as a form of energy

A
  • Macroscopic expression of the microscopic motion of atoms or molecules
  • Heat.(q): random motion/energy
  • Work (w): directed/organised motion/energy
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9
Q

Joule Experiment

A
  • heat and work can be interconverted
  • quantity of heat capable of increasing the temperature of one pound of water by 1 degree Farenheit requires the expenditure of a mechanical force (fall of 772 lbsby one foot)
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10
Q

Isolated System

A

No exchange of matter or energy

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11
Q

Closed System

A

Exchange of energy but not matter

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12
Q

Open System

A

Exchange of both matter and energy

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13
Q

Enthalpy

A
  • practical expression of the first law of thermodynamics
    H = U + (PV)
  • changes in enthalpy means heat has moved in/out of the system
  • enthalpy can be thermal energy or a phase transition
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14
Q

Heat capacity

A

The amount of heat to be supplied to a given mass of a material to produce a unit change in its temperature.
= q/T

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15
Q

Chemical forms of Enthalpy

A

Energy storage in a molecular system

  1. covalent bonds
  2. weak bonds
    - bond energy is a form of enthalpy without decreasing volume
    - enthalpy is molecular motion and organisation
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16
Q

Boltzman Constant

A

Kb = R / na

17
Q

Statistical View of Entropy

A
  • no work done or enthalpy changes
  • entropy (S) = Kb x ln Q
    Q = number of microstates corresponding to a particular macrostate
  • probability equation relating the entropy of the gas to the number of real microstates corresponding to the gas’s macrostate
  • shows the relationship between entropy and the possible number of ways the atoms/molecules can be arranged
18
Q

Thermodynamic view of entropy

A

S = nR ln (V2/V1)
S = q/T
Entropy of universe = entropy of system + entropy of surroundings
Based on the second law of thermodynamics

19
Q

Gibb’s Free Energy

A

G = H - TS

20
Q

Enthalpy Driven and Entropy Driven Reactions

A
  • reactions can be favorable entropically and enthalpically (exergonic)
  • sometimes one factor drives the spontaneity of the reaction
21
Q

Ligand Binding

A
Favorable:
- forming protein ligand bonds
- re organisation of water
Unfavorable:
- loss of ligand mobility
- breaking protein water and ligand water bonds and water water bonds

Overall, there is a decrease in entropy but a larger increase in enthalpy so the reaction is spontaneous and enthalpy driven

22
Q

Protein Folding

A

Favorable:
- internal H bond formation in protein
- internal van der Waals bonds in protein
- re organisation of water (hydrophobic effect)
Unfavorable:
- breaking protein water and water water bonds
- loss of conformational flexibility

23
Q

Chemical Potential

A
  • energy change during a chemical reaction or phase transition
  • dependent on both the intrinsic chemical energy of the system (chemical bonding) and the concentration of the molecule
  • difference in this is the potential energy difference to establish a diffusional equilibrium
24
Q

Free energy and equilibrium

A

G = -RT ln Keq

The standard free energy change of a reaction tells us the Keq when allowed to come to equilibrium

25
Q

Energy Coupling

A
  • Unfavorable reaction can be coupled to a favorable one to drive it spontaneously
    eg. ATP coupling to biological reactions
26
Q

Steady State Conditions

A
  • concentrations of reactants and products may be constant but not at equilbrium
  • this is often seen in cells
  • G = Go + RT ln [products]/[reactants]
27
Q

Electrochemical Reactions

A
G = -nFE
E = electric potential (volts)
\+ = favorable
- = non favorable
28
Q

Half reactions

A
  • redox reactions (either reduction or oxidation) with associated voltages
  • adding them together gives overall voltage and spontaneity
29
Q

Van’t Hoff Plot

A

Relates the change in Keq (ln Keq) to the Temperature (1/T)
y Intercept: S/R
slope: H/R

30
Q

Membrane Potential

A
Y = membrane potential
G = concentration and electrical potentials
-96 mV
G = RT ln (in/out) + z x F x Y
Negative inside and positive outside
31
Q

Nernst Equation

A

Y = -RT/zF x ln [in]/[out]

32
Q

Active Transport

A

ATP use to move ions out of the cell

Find G of ion movement and couple this to ATP hydrolysis (-52.7 kJ/mol)