Thermodynamics Conceptual
A quantity of a monatomic ideal gas expands to twice the volume while maintaining the same pressure. If the internal energy of the gas were U0 before the expansion, what is it after the expansion?
2 U0
When a wool blanket is used to keep warm, what is the primary insulating material?
Air
The noble gases, listed by increasing molecular weight, are He, Ne, Ar, Kr, Xe, and Rn. If samples of 1 mole each of these gases are placed in separate containers and heated to 300 K, which gas has the greatest internal energy and the molecules of which gas have the highest rms speed?
All the gases have the same internal energy, and the He has the greatest rms speed
Two one-liter containers each contain 10 moles of a gas. The temperature is the same in both containers. Container A holds helium (molecular mass = 4 u), and Container B holds oxygen (molecular mass = 16 u). Which container has the higher pressure and by what factor?
Both containers have the same pressure
The coefficient of area expansion is:
Double the coefficient of linear expansion (gamma = 2xalpha)
Area on a P-V diagram has units associated with:
Energy
As I use sandpaper on some rusty metal, the sandpaper gets hot because:
Frictional processes increase the internal energy of the sandpaper
Evaporation cools the liquid that is left behind because the molecules that leave the liquid during evaporation:
Have greater than average speed
Consider two containers with the same volume and temperature. Container One holds "dry" air--a mixture of nitrogen and oxygen. Container Two holds "moist" air. The "moist" air has the same ratio of nitrogen to oxygen molecules, but also contains water vapor. According to the ideal gas law, if the pressures are equal, the weight of the gas in Container One will be:
Heavier than the gas inside the second container
A steel plate has a hole drilled through it. The plate is put into a furnace and heated. The size of the hole's diameter then:
Increases
The thermal expansion of a solid is caused by:
Increasing the distance between equilibrium positions for the vibrating atoms
In an isovolumetric process by an ideal gas, the system's heat gain is equivalent to a change in:
Internal Energy
According to the first law of thermodynamics, the sum of the heat gained by a system and the work done on that same system is equivalent to which of the following?
Internal energy change
Twenty grams of a solid at 70°C is placed in 100 grams of a fluid at 20°C. Thermal equilibrium is reached at 30°C. The specific heat of the solid:
Is more than that of the fluid
On a P-V diagram, an ____ process is represented by a horizontal line.
Isobaric
Suppose the pressure of 20 g of an ideal monatomic gas is tripled while its volume is halved. What happens to the internal energy of the gas?
It increases
What a steel disk is heated, what happens to its moment of inertia?
It increases
The temperature of a quantity of ideal gas in a sealed container is increased from 0°C to 273°C. What happens to the rms speed of the molecules of the gas as a result of this temperature increase?
It increases but it less than doubles
Inside a house, stepping on a tile floor barefooted may feel almost cold, but stepping on carpet in an adjacent room feels comfortably warm. Why is this?
It's because the thermal conductivity of carpet is less than that of tile
The absolute temperature of an ideal gas is directly proportional to which of the following properties, when taken as an average, of the molecules of that gas?
Kinetic Energy
An adiabatic expansion refers to the fact that:
No heat is transferred between a system and its surroundings
During an isobaric process which one of the following does not change?
Pressure
If one's hands are being warmed by holding them to one side of a flame, the predominant form of heat transfer is what process?
Radiation
John rapidly pulls a plunger out of a cylinder. As the plunger moves away, the gas molecules bouncing elastically off the plunger are:
Rebounding at a lower speed than they would have if the plunger weren't removed
On a sunny day at the beach, the reason the sand gets so hot and the water stays relatively cool is attributed to the difference in which property between water and sand?
Specific heat
Sea breezes that occur near the shore are attributed to a difference between land and water with respect to what property?
Specific heat
Heat flow occurs between two bodies in thermal contact when they differ in what property?
Temperature
For an ideal gas of a given mass, if the pressure remains the same and the volume increases:
The average kinetic energy of the molecules increases
What happens when the temperature of an ideal gas contained in a box is increased?
The average speed of the molecules in the box will be increased
If heat is flowing from a table to a block of ice moving across the table, which of the following must be true?
The ice is cooler than the table
Metal lids on glass jars can often be loosened by running them under hot water. Why is this?
The metal has a higher coefficient of thermal expansion than glass so the metal expands more than the glass thus loosening the connection
In an isothermal process for an ideal gas system (where the internal energy doesn't change), which of the following choices best corresponds to the value of the work done on the system?
The negative of its heat intake
Why do vapor bubbles get larger in boiling water as they approach the surface?
The pressure in the water decreases as the bubble moves toward the surface
If an ideal gas does positive work on its surroundings, we may assume, with regard to the gas:
Volume increases
Which of the following best describes a substance in which the temperature remains constant while at the same time it is experiencing an inward heat flow?
substance undergoing a change of state