Concept Phy Chem Flashcards
An ideal gas will only be considered in the
following operating parameters:
High temperature, Low Pressure
Which of the following is false regarding absolute
zero?
a.All molecules will stop moving
b. Absolute zero can be achieved
c. Temperature is 0K
d. Temperature is 0R
Absolute zero can be achieved
For a real gas, what causes the deviation from
the ideal pressure at a molecular level?
a. Energy is lost for each collision against
the sides of the container
b. Energy is lost due to the collision of
molecules with one another
c. Intermolecularforces of attraction of the
molecules with one another
d. Molecules randomly hit the sides of the
wall with less force than usual
Intermolecular forces of attraction of the
molecules with one another
When gas molecules collide, they experience
_collision.
Perfectly elastic
Which of the following is false with KMT?
a. Gas molecules move in random motion
b. Due to collision of gas molecules with
each other, some kinetic energy is lost
c. The temperature of the whole system
does not change with time
d. The size of the molecules are negligible
Due to collision of gas molecules with
each other, some kinetic energy is lost
This is the pressure exerted by the gas molecules
that are in equilibrium with the liquid.
Vapor pressure
The internal energy of an ideal gas depends on:
Absolute temperature
The state of an ideal gas is changed in a closed
path 1→2→3→4→1. Which of the following is
true about the work done on the gas?
a. W12>0, W23=0, W34<0, W41=0
b. W12<0, W23=0, W34=0, W41>0
c. W12=0, W23>0, W34=0, W41<0
d. W12=0, W23<0, W34=0, W41>0
W12=0, W23<0, W34=0, W41>0
Which of the following is a characteristic of an
adiabatic process?
Q=0
A sample of an ideal gas has an internal energy
of U and is then compressed to 1⁄2 of its original
volume while the temperature stays the same.
What is the new internal energy of the ideal gas
in terms of U?
U
Which of the following is not conserved in any
process?
Entropy
An isentropic process is:
Reversible and adiabatic
Increasing the temperature of the cold reservoir__
the Carnot efficiency.
Decreases
If the entropy of a system decreases, the entropy
of its surroundings
Must always increase
The amount of heat absorbed when CO2 gas
reacts with a solid CaO to form solid CaCO3 is
measured in a bomb calorimeter. The data
obtained give a direct measure of:
ΔU
Heat required to raise the temperature of 1lbm
of water by 1 ̊F.
Calorie
Which of the following statements is/are true?
1. The criterion of equilibrium at constant temperature and pressure is dG=0.
2. For a reversible process, dS=dQ/T.
both
The general statement of the Third Law of Thermodynamics is attributed to:
Walther Nernst
The equilibrium intensive state of a system is described by specifying the temperature, pressure, and
Mole fractions
The fugacity of a real gas is equal to:
The pressure of an ideal gas which has
the same chemical potential as the real
Conceptual Question (Oct. 2021 PBE)
An adiabatic process is one in which the system
under investigation is thermally isolated so that
there is no exchange of heat with the
surroundings. Thus, the work done on a closed
system in an adiabatic process is
Equal to the increase in internal energy
of the system
Conceptual Question (Oct. 2021 PBE)
If enthalpy is defined as present in a constant
pressure process change of state, using the
relationship of ΔH=ΔU+ΔPV, where H is enthalpy,
U is the energy change in the system and PV
represents pressure and volume states,
determine the ΔU and ΔH of 1kg of water when
vaporized at constant temperature of 100 ̊C and
constant pressure of 101.35kPa. The specific
volumes of liquid and vapor water are 0.001041
and 1.67m3/kg. An amount of 2257kJ of heat is
added to the water.
ΔU=2087kJ; ΔH=2257kJ
Conceptual Question (Oct. 2021 PBE)
A certain gas confined in a cylinder by a piston,
where the initial pressure in the system is 7 bar
and the volume is 0.11 cubic meter. The piston is
held in place by latches and the apparatus is in
vacuum. Determine the change in energy when
the latches are removed suddenly and the gas
expands to double its initial volume and the
piston strikes the latches at the end of the
process.
No change
Conceptual Question (Nov. 2019 PBE)
State Le Chatelier’s Principle.
Le Chatelier’s principle states that when
a stress is placed on a system in
equilibrium, the system tends to change
in a way that relieves the stress.
Determine which of the following occurrences
tells us what happens when Le Chatelier’s
principle is applied whether these are true or
false.
1. The addition of a component causes the
equilibrium to shift to the opposite side
2. The removal of a component causes the
equilibrium to the side from which the
component is removed
3. Increasing the temperature drives an
exothermic reaction to the side of the
reactants, an endothermic equilibrium
to the side of the products
4. The addition of a catalyst has NO effect
on the position of the equilibrium
T, T, T, T
Determine whether the changes in entropy (ΔS)
and enthalpy (ΔH) are positive, negative, or near
zero.
1. Ethyl alcohol evaporating from glass
container
2. A diatomic molecule dissociates into
atoms
3. Charcoal is burned to form CO2 and
water
ΔH>0, ΔS>0; 2. ΔH>0, ΔS>0; 3. ΔH>0,
ΔS>0
Conceptual Question (Nov. 2019 PBE)
Choose the process that occurs with a decrease
in entropy.
Freezing of water
Conceptual Question (Nov. 2019 PBE)
Which of the following does not have a zero
enthalpy of formation at 298.15K?
a.Li(g)
It is the property of a fluid that is caused by
shearing effect of a fluid layer moving past
another layer.
Viscosity
The Clapeyron Equation gives the slope:
dP/dT
The Clausius-Clapeyron Equation does NOT apply
to:
a. S-V equilibrium
c. S-L equilibrium
b. L-V equilibrium
S-L equilibrium
Conceptual Question (Nov. 2019 PBE)
What is the Clapeyron Equation?
a. Any of these
b. It postulates that the colligative
properties, freezing point depression,
boiling point elevation, osmotic
pressure, and vapor pressures are all
dependent on the number f particles in
the solution and any change thereof is
described.
c. It postulates that if two components
systems consisting of solid and liquid
phases are miscible in the liquid state
and immiscible in the solid state, only
the pure solid systems will separate out
on cooling solutions.
d. It postulates that if the temperature and
pressure are both change in such a way
asto keep the chemical potentials of two
phases equal to each other, the rates of
change are given by the equation.
d. It postulates that if the temperature and
pressure are both change in such a way
asto keep the chemical potentials of two
phases equal to each other, the rates of
change are given by the equation.
Conceptual Question (Oct. 2021 PBE)
The coexistence curve where the plot of pressure
versus temperature along which the two phases
coexist was shown by Clausius-Clapeyron. What
did Clausius postulate?
The Clapeyron equation was simplified
by assuming that the vapor obeys the
ideal gaslaw and by neglecting the molar
volume of the liquid VL in comparison
with the molar volume of the gas VG
For miscible systems, the boiling point of the
solution is:
Between the boiling points of
the two liquids
All colligative properties stem from the _ of
the chemical potential of the liquid solvent as
a result of the presence of the solute.
Reduction
In a process involving osmosis, at equilibrium,
the chemical potential of the pure solvent side
should be__ the chemical potential of the
side with solute.
Equal to
When a solute is introduced to a liquid system, the
entropy of the said system:
Increases
Among the following, which compound will
produce the least lowering of the vapor pressure
of a solution?
sucrose, C12H22O11
Which of the following statements is true?
a. Trouton’s rule fails for highly polar
liquids
b. It is impossible to go from vapor phase
to liquid phase without condensation
c. For C compounds and P phases, there
are a total of CP intensive variables to be
specified
d. At high pressures, the latent heat of
vaporization is a measure of the strength
of the intermolecular forces of the liquid
Trouton’s rule fails for highly polar
liquids
Conceptual Question (Nov. 2019 PBE)
Are galvanic cells and electrolytic cells the
same? Why?
No. because galvanic cells are
electrochemical cells in which
chemical cells occur simultaneously;
while in electrolytic cells, the chemical
reaction is caused by an externally
applied potential difference.
Significance of colligative property in physical chemistry
it refers to the freezing point depression, boiling point elevation, osmotic pressure and lowering of the vapor pressure by a non volatile solute.
