Physical Chemistry Flashcards
An ideal gas will only be considered in the following operating parameters
a. High T, High P
b. High T, Low P
c. Low T, High P
d. Low T, Low P
b.
Which of the following is false regardung absolute zero
a. Absolute zero can be achieved
b. All molecules will stop moving
c. Temperature is 0Kelvin
d. Temperature is 0Rankine
a.
Absolute zero is a THEORETICAL state and cannot be achieved
For a real gas what causes deviation from the ideal pressure at the 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. Intermolecular forces of attraction of the molecules with one another.
d. Molecules randomly hit the sides of the wall with less force than usual.
c
when gas molecules collide, they experience ________ collision
a. Perfectly elastic
b. Imperfect elastic
c. Perfectly inelastic
d. Imperfect inelastic
a
Perfectly elastic - bounces off
Inelastic - deforms
Perfectly Inelastic -sticks together
Explosion - reverse of Perfectly inelastic
Which of the following is false with KMT
a. gas molecules move in random motion.
b. The temperature of the whole system does not change with time
c. Due to collision of gas molecules with each other, some kinetic energy is lost
d. The size of the molecules are negligible
c because it is perfectly elastic, meaning KE is preserved
This is the pressure exerted by the gas molecules that are in equilibrium with a liquid
Partial Pressure
Atmospheric Pressure
Total Pressure
Vapor Pressure
Vapor Pressure
The internal energy of an ideal gas depends on
Volume
Absolute Temperature
Pressure
Number of moles
Absolute Temperature
Which of the following is a characteristic of an adiabatic process
a. delta U=0
b. W=0
c. Q=0
d. delta V=0
c
which of the following is not conserved in any process?
Mass
Energy
Momentum
Entropy
Entropy
Increasing the temperature of the cold reservoir ______ the Carnot Efficiency
Inc
Dec
Does not change
Decreases
If the entropy of a system decreases, the entropy of its surroundings
a. Must always increase
b. Must always decrease
c. May increase or decrease
d. Not enough information to answer the question
a
- because Delta S univ > 0 meaning if S system decreases, S surroundings will always increase to counteract it
The amount of heat absorbed when CO, gas reacts with a solid CaO to form solid CaCO, is measured in a bomb calorimeter. The data obtained give a direct measure of:
a. Delta U
b. V delta P
c. delta H
d. Cp
a
- because Bomb Calorimeter is V=k
Heat required to raise the temperature of 1lb of water by 1F
BTU
Heat required to raise the temperature of 1g of water by 1C
Calorie
Which of the following statements is/are true?
- The criterion of equilibrium at constant temperature and pressure is dG=0.
- For a reversible process, dS=dQ/T.
a. 1 only
b. Both 1 and 2
c. 2 only
d. None of the above
b
The general statement of the Third Law of Thermodynamics is attributed to:
a. Nikolaus Otto
b. Jacobus Clapeyron
c. William Clausius
d. Walther Nernst
d
• In 1912 Walther Nernst was able to formulate the third law of thermodynamics, which made it possible to calculate chemical equilibriums on the basis of the heat exchange.
The equilibrium intensive state of a system is described by specifying the temperature, pressure, and:
a. Mole fractions
b. Number of moles
c. Volume
d. Chemical potential
a.
The fugacity of a real gas is equal to:
a. The pressure of an ideal gas which has the same chemical potential as the real gas
b. The pressure of a real gas which has the same chemical potential as the ideal gas
C. The chemical potential of an ideal gas which has the same pressure as the real gas
d. The chemical potential of a real gas which has the same pressure as the ideal gas
a
(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
a. Equal to zero
b. Not equal to the exchange of heat with surroundings
c. Equal to the increase in internal energy of the system
d. Not equal to the increase in internal
energy of the system
c
(Nov. 2019 PBE)
State Le Chatelier’s Principle.
a. 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.
b. All of these
c. Examples of the application of Le Chatelier’s principle are blowing your breath through a straw and dissolving alka seltzer tablet in a glass of water.
d. Le Chatelier’s principle explains both the formation and decomposition of acids, where anything that might act to increase the concentration of an acid would produce an increase in the other components so as to keep the numerical
a
(Nov. 2019 PBE)
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
d. All of these
d
A method for determining the mol weight of gas that is gaseous at room temperature
Regnault’s Method
A method for determining mol weight of gas in vapor phase of readily volatile liquids
Dumas Method
It is the adhesion of atoms, ions, or molecules from a gas, liquid or dissolved solid to a surface.
Adsorption
At absolute zero, all substances would be in the _________ phase, and all particles would have __________kinetic energy.
solid, zero
Asolute zero is equal to zero in the ___________ temperature scale
Kelvin
Considered the fourth state of matter
Plasma
It is a mixture of neutral atoms, charged ions, and free electrons
Plasma
special state of matter in which atoms in a confined gas act together like a single giant particle after being cooled cryogenically to a temperature near absolute zero
Bose-Einstein Condensate
Molecular weight determination
Having various pressures and constant temperature. Use:
a. Method of Limiting Density
b. Vapor density Method
c. Regnault Method
a
Molecular weight determination
Determining molecular weight in vapor phase of volatile liquid. Use:
a. Method of Limiting Density
b. Vapor density Method
c. Regnault Method
b
He developed Vapor Density Method
Jean Baptiste Andre Dumas
Molecular weight determination
Determining molecular weight of a gas at room temp. Use:
a. Method of Limiting Density
b. Vapor density Method
c. Regnault Method
c
Compression factor Z for ideal gas
1
The temperature at which the property of a real gas coincides with that of an ideal gas
Absolute temp
Ideal Temp
Boyle Temp
Transitioning temp
Boyle Temperature
It means that the vapor pressure of the system is in equilibrium with its liquid state
Saturated vapor pressure
At critical point, physical properties of liquid and vapor are ______
equal
Amount of work required to increase the surface area of a liquid by one unit of area
Surface Tension
-property of a liquid that allows it to resist an external force
It is the existence of substances in more than one modification
Polymorphism
In electrolytic cells, the anode is _______ and the cathode is ________
positive
negative
positive, negative
In galvanic cells, the anode is _______ and the cathode is ________
positive
negative
negative, positive
“The mass of a substance involved in the reaction at the electrode is proportional to the quality of electricity passes through the solution”
Faraday’s Law
According to this law, at constant pressure and temperature, molecules or atoms with lower molecular mass real a few faster than the higher molecular mass molecules or atoms.
Graham’s Law
- lighter gas will travel faster than heavier gas
The fastest gas
Helium
according to Graham, slow rate of effusion of gas is inversely proportional to the square root of its
atomic mass
molecular mass
molar mass
isotopic mass
molecular mass
Which of the following statement is CORRECT about ideal gas?
a. The pressure of the gas is equal to the total kinetic energy of the molecules in a unit volume of the gas
b. The product of pressure and volume of the gas is always constant
c. The average kinetic energy of molecule of the gas is proportional to its absolute temperature
d. The average kinetic energy of molecule of the gas is proportional to the square root of its absolute temperature
c
absolute zero maybe regarded as that temperature at which
a. all gases becomes liquid
b. molecular motion ceases
c. all substances are solids
d. water freezes
b
if a given gas has a compressibility factor, Z>1, this means that ___________ between the molecules of gases
a. attractive forces
b. repulsive forces
c. negligible forces of attraction
d. negligible replusive forces
b.
Z>1 rep forces ate dominant
Z<1 att forces are dominant
Z inc with P
Generally, viscosity of gases _______ as temperature increases
a. remains constant
b. increases
c. approaches unity
d. decreases
b
Fluids whose viscosity increases as shear rate increases.
a. Dilatant
c. Newtonian
b. Pseudoplastic
d. Bingham plastic
Dilatant
-shear thickening = increasing viscosity as more force is applied
ex: oobleck
• Newtonian - constant viscosity, with zero shear rate at zero shear stress, that is, the shear rate is directly proportional to the shear stress.
ex : water
• Pseudoplastic - shear thinning; decrease in viscosity when more force is applied
• Bingham - behaves as a rigid body at low stresses but flows as a viscous fluid at high stress.
Fluids whose viscosity increases with time at constant shear rate.
a. Inviscid
b. Rheopectic
c. Thixotropic
d. Pascalian
b
• Inviscid - negligible viscosity and shear rate. no viscosity.
• Thixotropic - viscosity decreases with time at constant shear rate.
• Pascalian - pressure at any point in the fluid is equal in all direction
What happens to the molecules in a liquid when the liquid is heated and vapor starts to form?
a. the intramolecular forces between liquid molecules are disrupted
b. the intermolecular forces between liquid molecules are disrupted
c. kinetic energy is removed from the system
d. London forces become stronger
b
• Intramolecular forces are the forces that hold atoms together within a molecule.
• Intermolecular forces are forces that exist between molecules
One colligative property of solutions is its freezing point depression. Which observation will show that the solute is an electrolyte (Delta Tf/m)?
a. is not a constant
c. is less than Kf
b. is not Kf
d. is greater than Kf
d
Which of these 0.1 m solutions will give the highest boiling point at 1 atm?
a. table salt solution
c. barium chloride
b. sugar solution
d. potassium chloride
b.
higher MW, higher conc = higher BP
All the half cell potential e°, use the ______ as the reference
Hydrogen electrode
oxygen half cell
carbon half cell
arbitrary net zero point
a
An electrochemical cell in which chemical reaction is forced to occur by the application of an outside source of energy is
a. galvanic
b. electrolytic
c. electrical
d. chemical
b
The more negative the value of e°, the more likely the reaction is to proceed from
a. left to right
b. right to left
c. either way
d. can’t be determined
b
Which of the following statements about colligative properties is TRUE?
a. Both vapor pressure and freezing point INCREASE when a non- volatile
solute is added to a solvent.
b. Both freezing point and boiling point INCREASE when a non- volatile
solute is added to a solvent.
c. Both vapor pressure and boiling point DECREASE when a non- volatile
solute is added to a solvent.
d. Colligative properties depend only upon the NUMBER of solute particles in a solution and not upon their identity.
d
The vapor pressure of a liquid
a. always increases with temperature
b. always decreases with temperature
c. is independent of temperature
d. none of these
a
The law relating the solubility of the gas to its pressure is called
a. Raoult’s Law
b. Distribution Law
c. Henry’s Law
d. Arrhenius’ Law
b
When gaseous ammonia is dissolved in water, the resulting solution does not obey Henry’s Law. Which of the following best explains why this solution does not obey Henry’s Law?
a. All of the NH, that initially dissolves in the water rapidly escapes from the solution because NH, is a gas at room temperature
b. NH, reacts with the solvent to produce ammonium and hydroxide ions
c. NH, is not soluble in water because it is a non-polar molecule.
d. The hydrogen bonding between ammonia molecules is so strong that NH, cannot be dissolved in water.
b
Henry’s Law
C=k*P
k- Henrys constant
P- Partial pressurr
For a chemical reaction in a state of equilibrium, a decrease in temperature will
a. favor the reaction that is exothermic
b. favor the reaction that is endothermic
c. have no effect on the system
d. increase the equilibrium constant of the system
a
The system counteracts the change by producing more heat.
In a chemical reaction, equilibrium has been established when the
a. opposing reaction ceases
c. reaction ceases to generate heat
b. concentrations are equal
d. net velocities of reactions is zero
d
• In a reversible chemical reaction, equilibrium is said to have been established when the speeds of opposing reactions become equal. Neither the forward reaction nor the backward reaction has ceased.
• Hence, the state of equilibrium refers to the dynamic state
For a chemical reaction in a state of equilibrium, an increase in temperature will
a. favor the reaction that is exothermic
b. favor the reaction that is endothermic
c. have no effect on the system
d. increase the equilibrium constant of the system
b
The system counteracts the change by absorbing the extra heat.
