課程名稱︰普通化學乙上
課程性質︰系定必修
課程教師︰化學系副教授金必耀
開課學院：工學院
開課系所︰土木系
考試日期（年月日）︰96/01/19
考試時限（分鐘）：10:20~12:30
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試題 :
problem1
Why is ΔH obtianed directly from the heat flow using a coffee cup calorimeter
and ΔE obtained from the heat flow using a bomb calorimeter.
problem2
Consider 1.0mol of a monatomic ideal gas in a container fitted with a piston.
The initial conditions are 10.0L and P=10.0atm
1.If the external pressure is suddendly changed to 2.0 atm, calculate the
ΔH,ΔE,q,w,ΔS,ΔG for the process. Is this a spontaneous process? Why?
2.Calculate the ΔH,ΔE,q,w,ΔS,ΔG for the same change of pressure as in part1
but performed isothermally and reversibly.
3.Construct the PV diagrams for processes described in parts 1 and 2.
4.Calculate the entropy change in the surroundings for process described
in parts 1 and 2.
problem3
Consider the system
A(g)→B(g) at 25度C
1.Assuming that G(oA)=8996J/mol and G(oB)=11718J/mol, calculate the value of
the equilibrium constant for this reaction.
2.Calculate the equilibirum rressure that result if 1.00molA(g) at 1.00atm
and B(g) at 1.00 atm are mixed at 25度C.
3.Show by calculations that ΔG=0 at equilibrium.
problem4
Liquid water at 25度C is introduced into an evacuated insulated vessel.
Identify the signs of the following thermodynamic functions for the process
that occurs:ΔH,ΔS,ΔG,ΔSsurr,ΔSuniv,ΔTwater.
problem5
Consider the process
A(l)75度C→A(g)155度C
Which is carried out at constant pressure.The total ΔS for this process is
known to be 75.0J/Kmol. For A(l) and A(g), the Cp values are 75.0 J/Kmol and
29.0 J/Kmol, respectively, and are not dependent on temperature. Calculate
ΔHvap for A(l) at 125度C(its boiling point).
problem6
Hydrogen is more energy-dense than carbon, by mass. Thus, historially there
has been a move toward fuel with higher hydrogen content:coal→oil→
natural gas→hydrogen. Cost-effective production and safe storage of hydrogen
are two major hurdles to the successful inauguration of a hydrogen economy.
1.Consider hydrogen in a cylinder of 80MPa at 25度C. Using the ideal gas law,
estimate the density of hydrigen in the cylinder in kg/m^3.
2.Calculate the ratio between heat generated when hydrogen is burned and heat
generated when the same weight of carbon is burned. The difference comes to a
large extent from the fact that the most abundant isotope of hydrigen has no
neutron and hydrogen has no inner electron shell.
ΔH(of)[H20(l)]=-286kJ/mol, ΔH(of)[CO2(g)]=-394kJ/mol.
3.Calculate the theoretical maximum work produced by the conbution of 1 kg
hydrogen(a)from the electric motor using hydrogen fuel cell and (b)from the
heat engine working between 25度C and 300度C. The efficiency(work done/heat
absorbed) of an ideal engine working between Tcold and Thot is given by
1-Tcold/Thot.
S(o298)[H2(g)]=131J/(Kmol)
S(o298)[O2(g)]=205J/(Kmol)
S(o298)[H2O(g)]=70J/(Kmol)
If the fuel cell is working at 1W and the standard potential difference, how
long will the electric motor run at what current?
problem7
Combine the equations
ΔG(o)=-nF€(o) and ΔG(o)=ΔH(o)-TΔS(o)
to derive an expression for €(o) as a function of temperature. Describe how
one can graphically determine ΔH(o) and ΔS(o) from measurements of €(o) at
different temperatures. Assume that ΔH(o) and ΔS(o) do not depend on temperature.
problem8
The efficiency of a drug is greatly dependent on its ability to be absorbed
into the blood stream. Acid-base chemistry plays an important role in drug
absorption.
Membrane
Stomach | Blood
pH=2.0 | pH=7.4
H+ + A- → HA → HA → H+ + A-
← ← ←
|
Assume that the ionic form(A-) of a weakly acidic drug does not penetrate the
membrane, whereas the neutral form(HA) freely crosses the membrane. Also assume
that equilibrium is established so that the concentration of HA is the same on
both sides. Calculate the ratio of the total concentration([HA]+[A-]) of
aspirin (acetylsalic acid, pK=3.52) in the blood to that in stomach.
Problem 9 LaChatelier Principle
In which direction will the position of the equilibrium
2HI(g)=H2(g)+I2(g)
be shifted for each of the following change?
1.H2(g) is added.
2.I2(g) is removed.
3.HI(g) is removed.
4.Some Ar(g) is added.
5.The volume of the container is double.
6.The temperature is decreased (the reaction is exothermic).
Problem 10 Extra Credit: Ligand-binding problem
A protein M bind two molecules of a ligand L, which is a gas. The macroscopic
equilibrium constants, written in terms of the partial pressure of the ligand
, are defined by
M + L = ML K1 = [ML]/[M]PL
ML + L = ML2 K2 = [ML2]/[ML]PL
Assume that the two binding sites are identical, i.e. ML cannot be
distinguished from LM. How are the microscopic dissociation constants
M + L = ML K1 = [ML]/[M]PL
M + L = LM K1 = [LM]/[M]PL
ML + L = LML K2 = [LML]/[ML]PL
LM + L = LML K2 = [LML]/[LM]PL
related to the macroscopic equilibrium constant K1 and K2?