Midterm 2 Flashcards
What would be the greatest effect of the finite size of molecules on the ideal gas law?
At high densities, the pressure would be less than that predicted by the ideal gas law.
What would be the greatest effect on the ideal gas law if there is a slight attractive force between the molecules?
At low temperatures, the pressure would be less than that predicted by the ideal gas law.
What would be the greatest effect on the ideal gas law if there is a slight repulsive force between the molecules?
At low temperatures, the pressure would be greater than that predicted by the ideal gas law.
The average molecular kinetic energy of a gas can be determined by knowing only the – of the gas.
temperature
A sample of an ideal gas is slowly compressed to one-half its original volume with no change in temperature. What happens to the average speed of the molecules in the sample
It does not change.
A container is filled with a mixture of helium and oxygen gases. A thermometer in the container indicates that the temperature is 22°C. Which gas molecules have the greater average kinetic energy?
It is the SAME for both because the temperatures are the same.
A container is filled with a mixture of helium and oxygen gases. A thermometer in the container indicates that the temperature is 22°C. Which gas molecules have the greater average speed?
The helium molecules because they are less massive.
Phase change occur as the temperature
remains the same
The point in the phase diagram where the fusion curve, the vapor pressure curve, and the sublimation curve join is called the
triple point
The point in the phase diagram where the vapor pressure curve ends is called the
critical point
When a solid melts, heat energy – the substance
enters
When a liquid freezes, heat energy – the substance
leaves
By what primary heat transfer mechanism does one end of an iron bar become hot when the other end is
placed in a flame?
conduction
The type of heat transfer that occurs between a stove and a pot placed on it is
conductive
The type of heat transfer that occurs between the radiator of a car and the atmosphere, when the car is in
motion, is principally
convective
The type of heat transfer that occurs between warm food and the air in the room is principally
convective
Convection can occur
only in liquids and gases
The process whereby heat flows in the absence of any medium is referred to as
radiation
The process whereby heat flows by the mass movement of molecules from one place to another is referred to
as
convection
The process whereby heat flows by means of molecular collisions is referred to as
conduction
Consider two cylinders of gas identical in all respects except that one contains O2 and the other He. Both hold the same volume of gas at STP and are closed by a movable piston at one end. Both gases are now
compressed adiabatically to one-third their original volume. Which gas will show the greater pressure increase?
the He
Consider two cylinders of gas identical in all respects except that one contains O2 and the other He. Both hold the same volume of gas at STP and are closed by a movable piston at one end. Both gases are now
compressed adiabatically to one-third their original volume. Which gas will show the greater temperature increase?
the He
An ideal gas starts in state A at temperature T. The gas expands to new volume V by an adiabatic process
and its final temperature is T’. What is the relationship between T and T’?
T > T’
When a gas expands adiabatically,
the internal energy of the gas decreases
During which type of process applied to an ideal gas is there no change in internal energy of the gas?
isothermal
During which type of process applied to an ideal gas is there no heat added to the gas?
adiabatic
During which type of process applied to an ideal gas is there no work done by the gas?
isochoric
When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an
isochoric process,
W = 0
When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an
adiabatic process,
Q = 0
When the first law of thermodynamics, Q = ΔU + W, is applied to an ideal gas that is taken through an isothermal process,
ΔU = 0
Is it possible to transfer heat from a cold reservoir to a hot reservoir?
Yes, but work will have to be done
The internal energy of an ideal gas is changed by adding heat Q to the system and also by doing work W on
the gas. What is the change in internal energy of the gas?
Q + W
A chunk of ice (T = -20°C) is added to a thermally insulated container of cold water (T = 0°C). What happens
in the container?
Some of the water freezes and the chunk of ice gets bigger
The heat required to change a substance from the liquid to the vapor state is referred to as the
hear of vaporization
The heat required to change a substance from the solid to the liquid state is referred to as the
heat of fusion
A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the
aluminum and the copper are in thermal contact. The specific heat capacity of aluminum is more than
double that of copper. Which object experiences the greater temperature change during the time the system
takes to reach thermal equilibrium?
it is impossible to tell without knowing the masses
A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the
aluminum and the copper are in thermal contact. The specific heat capacity of aluminum is more than
double that of copper. Which object experiences the greater magnitude gain or loss of heat during the time
the system takes to reach thermal equilibrium?
neither; both experience the same size gain or loss of heat
It is a well-known fact that water has a higher specific heat capacity than iron. Now, consider equal masses
of water and iron that are initially in thermal equilibrium. The same amount of heat, 30 calories, is added to
each. Which statement is true?
They are no longer in thermal equilibrium; the iron is warmer.
A cup of water is scooped up from a swimming pool of water. Compare the temperature T and the
internal energy U of the water, in both the cup and the swimming pool.
TPool is equal to TCup, and UPool is greater than UCup
closed system in which NO ENERGY in any form is transferred
isolated system
NO MASS enters or leaves but energy may be exchanged
closed system
mass and energy transfer
Open system
