CHE 3190
Survey of Physical Chemistry (Fall 2015)
G.Lind
STUDY GUIDE FOR
EXAM 3
Fenn CH 4 : Back to Work
Study the lecture notes
Calculate work for different paths, including geometrically (area under curve)
Work going different ways on path (forward, backward)
Fenn CH 5 : More in re Heat
q = mc(Tf – Ti) = C D T
c = specific heat
C = cm = (specific) heat capacity
C
= molar heat capacity (units : Jmol-1 ) ;
n
m
;
n = amount of substance (mol) ;
n=
M
C = n C = m C ; C = MC
C=
C=
C
= specific heat capacity (units : Jg-1)
m
m = mass (g)
;
M = molar mass (gmol -1)
1.0000 cal = 4.1845 J
C increases with the complexity of the molecule :
Equipartition Theorem :
1
1
1
Cu = Rftrans + Rfrot + 2 Rfvib = molar heat capacity at constant volume at high T
2
2
2
1
1
Cu = Rftrans + Rfrot = molar heat capacity at constant volume at low T
2
2
Total degrees of freedom (f) = 3N
with N = number of atoms in molecule
linear molecule : fvib = 3N - 5
;
nonlinear molecule : fvib = 3N - 6
C p = Cu + R
Fenn CH 6 : The Origin of Cycle Analysis
Carnot Cycle : Step I : isothermal , Step II : adiabatic : Step III : isothermal , Step IV : adiabatic ;
Know how to calculate Pf , Vf , Tf , q , w , D U , D H for :
(a) Isothermal change
(b) Isochoric change
(c) Isobaric change
(d) Adiabatic change
e=
-w
general
qadd
;
e(Carnot) =
TH - TC
TH
only for Carnot cycle
Fenn CH 7 : Heat is Work and Work is Heat. But Energy's the Difference
First Law : dU = dq + dw
DU = q + w
Sign convention ( + is in, - is out)
w = won , q = qadd
1
D Ucycle = 0
Fenn CH 8 : Two Laws from One Dilemma
dU = dq - PdV
H = U + PV
dqv = D U ;
dqp = D H
U = U(T) and H = H(T) for ideal gas
dU = Cv dT and dH = Cp dT for ideal gas
DU
= n C u (Tf
- Ti )
adiabatic change :
DH
;
= n C p (Tf
g
PV = const
- Ti )
and
TV g -1 = const
Fenn CH 9 :All in a Nutshell
Good summary
Fenn CH 10 : HER Has Much to say
Pages 166 - 175
Thermal Pollution by Power Plants
TC
qc
general ; c(Carnot) =
only for Carnot cycle
TH - TC
w
TH
-qH
Heat pump : coefficient of performance b =
general ; b (Carnot) =
only for Carnot cycle
TH - TC
w
Refrigerator : coefficient of performance
c=
Fenn CH 12 : Enter Entropy
Pages 210 -226
Definition of Entropy
Computation of Entropy changes : reversible phase change
Processes : isothermal, isochoric, isobaric, adiabatic, general
Reversible, irreversible changes
CHEAT SHEET:
(8.5x11 in), both sides, everything handwritten (no copies), no answers to end of chapter problems or PEs or DQs.
Your name must be on the sheet.
Sheets has to be handed in with the exam.
2