5d Flashcards

1
Q

is entropy a state function

A

yesssss

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2
Q

entropy is a function of

A

volume,, temp + number of moles of an ideal gas!!

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3
Q

in an ideal gas,, what does internal energy depend on

A

depends on temperature only

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4
Q

what is the driving force of chemical change

A

chemical potential

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5
Q

what does chemical potential do

A

it helps us predict the direction of a chemical reaction

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6
Q

what can internal energy be expressed as a function of

A

heat
work
change in molar of reactants aka how much there are.

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7
Q

the probability factor between change in molar amount and change in internal energy for a species called ‘i’ is

A

long u.

also known as chemical potential

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8
Q

dU = in terms of chem potential, temp and entropy , pressure and volume

A

TdS - pdV + u1 dN1 + u2 dN2

aka dU = TdS - pdV + (sum of chem potential of smt x by the number of molecules there are of it.)

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9
Q

okay so what does chemical potential depend on

A

depends on
S
V
Nk

aka chemical potential helpus us predict the direction of a chemical potential : so entropy, number of molecules or volume

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10
Q

dS in terms on internal and environment

A

dS = diS + deS.

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11
Q

whats dN in terms of i and e

A

dN = diN + deN

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12
Q

is mass exchanged in a closed system

A

nope

only energy

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13
Q

the entropy of an isolated system continues to increase bc of what

A

due to irreversible processed

diS > 0

U and V stays unchanged // constant

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14
Q

maximum entropy

A
  • entropy of a system continues to increase if its an irreversible reaction bc diS > 0

when U and V stays unchanged

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15
Q

minimum energy

A

at constant entropy and volume

S and V

the system can reach minimum energy

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16
Q

max entropy needs what to be maximalised

A

max entropy needs
an isolated system
where diS > 0 occurs

where U and V are constant

17
Q

min energy needs what to stay constant

A

it needs constant S and V

18
Q

if smt is constant,, what would its d value be. aka if V is constant

A

dV = 0

19
Q

dU in terms of T, S, p, V , diS

A

dU = TdS - pdV - TdiS

20
Q

at constant T and V Helmholtz free energy in a closed system =

A

F = U -TS

21
Q

at constant temp and volume,, in an irreversible process,, what would the value of F be

A

it would be at a minimum

22
Q

what is gibbs energy // what does it correspond to

A

it corresponds to the max amount of energy available for doing work

implaying its a reversible reaction

23
Q

what is the minimum gibbs energy

A

H -TS

if pressure and temperature are kept constant in a closed system

24
Q

gibbs equals to H - TS but what else does it equal to

A

U + pV - TS

25
Q

what is affinity

A

the extent of reaction + chemical potential

26
Q

what is the symbol for chemical potential again

A

long u

27
Q

when were talking about affinity in an equation,, aka the extent of reaction + chemical potential, what part is the chemical potential bit

A

the long u + long u - long u

where u do reactants - products

28
Q

a non vanishing affinity means what

A

implies that a system is not at equilibrium

29
Q

when can gibbs free energy be minimised

A

when pressure and temp is constant

in irreversible conditions

the extent of reaction (§) will reach §eq. where gibbs is at the minimum

think of a sloped curved line. with gibbs on the y axis and extent of reaction,§, on the x axis.

where u have §eq. aka the middle of the x axis,, this is where gibbs is lowest

-A = (dG/d§) p,T

30
Q

to find out more about how maximalised entropy controls proccesses what do we need to look at

A

we need to look at calculating the mixing entropy of two different gases wwith the same number of moles,, N,, and we need to make sure that they occupy the same volume.

at constant temperature.

1 + 1 = 2 for the total volume

31
Q

change in S mix when were trying to see how entropy maxing controls processes,, how do we find delta S mix

A

delta S mix = deltaS final - deltaS initial.

32
Q

entropy of an ideal gas is affected by what

A

V
N
T

33
Q

in equations,, what is Xk

A

mole fraction
Nk / N1 + N2

34
Q

the number of microstates formed through the mixing process is equal to what:

A

W = (NaN1 + NaN2)! /
(Na N1)! (Na N2)!

35
Q

delta S mix can also be found using what equation

A

the kb one

delta S mix = kB ln(Wmix)

36
Q

R =

A

Na KB

37
Q

ln( A/B) can also be found in what way

A

ln(a) - ln(b)