Physical Chemistry 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?
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
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?
A. Mass
B. Energy
C. Momentum
D. Entropy
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
Enthalpy can be expressed as a function of T and P. This relationship is shown by:
dH = CpdT + [ V - T (dV/dT)P ] dP
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.
BTU
Which of the following statements is/are true?
1. The criterion of equilibrium at constant
2. For a reversible process, dS = dQ/T
Both 1 and 2
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 gas
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
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.
- The addition of a component causes the equilibrium to shift to the opposite side
- The removal of a component causes the equilibrium to the side from which the component is removed
- Increasing the temperature drives an exothermic reaction to the side of the reactants, an endothermic equilibrium to the side of the products
- The addition of a catalyst has NO effect on the position of the equilibrium
T, T, T, T
Define entropy.
A. Entropy is a function of the state of the system and determines whether a physical change or chemical reaction can occur simultaneously in a closed system
B. Entropy is the opposite of enthalpy
C. Entropy determines the time required for a reaction to proceed and complete
All of these
Determine whether the changes in entropy (ΔS) and enthalpy (ΔH) are positive, negative, or near zero.
- Ethyl alcohol evaporating from glass container
- A diatomic molecule dissociates into atoms
- Charcoal is burned to form CO2 and water
- ΔH>0, ΔS>0; 2. ΔH>0, ΔS>0; 3. ΔH>0, ΔS>0
Choose the process that occurs with a decrease
in entropy.
Freezing of water
Which of the following does not have a zero enthalpy of formation at 298.15K?
A. Li (g)
B. He (g)
C. Hg (l)
D. Br2 (l)
Li (g)
Gross Heat of Combustion
Higher Heating Value (HHV)
- water is liquid
Net Heat of Combustion
Lower Heating Value (LHV)
- water is vapor
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:
S-L equilibrium
What is the Clapeyron Equation?
It postulates that if the temperature and pressure are both change in such a way as to keep the chemical potentials of two phases equal to each other, the rates of change are given by the equation.
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 gas law 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
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.
