Unit 6 Thermodynamics Physics

What temperature has the same numerical value on both the Fahrenheit and the Celsius scales? a. -40.0° b. 0° c. 40.0° d. -72.0°

a. -40.0°

When 4 grams of a substance loses 4 calories in cooling 1°C, its specific heat capacity using water as the unit of measure, is _____. a. 1 b. 6 c. 10 d. 20 e. none of the above

a. 1

A nail is driven into a board with an initial kinetic energy of 150 J. If the potential energy before and after the event is the same, what is the change in the internal energy of the board and nail? a. 150 J b. 75 J c. 0 J d. -150 J

a. 150 J

A substance registers a temperature change from 20°C to 40°C. To what incremental temperature change does this correspond? a. 20 K b. 40 K c. 36 K d. 313 K

a. 20 K

What happens to the internal energy of an ideal gas when it is heated from 0°C to 4°C? a. It increases. b. It decreases. c. It remains constant. d. It is impossible to determine.

a. It increases.

A heat engine has taken in energy as heat and used a portion of it to do work. What must happen next for the engine to complete the cycle and return to its initial conditions? a. It must give up energy as heat to a lower temperature so work can be done on it. b. It must give up energy as heat to a higher temperature so work can be done on it. c. It must do work to transfer the remaining energy as heat to a lower temperature. d. It must do work to transfer the remaining energy as heat to a higher temperature.

a. It must give up energy as heat to a lower temperature so work can be done on it.

A chunk of ice with a mass of 1 kg at 0°C melts and absorbs 3.33 * 10^5 J of heat in the process. Which best describes what happened to this system? a. Its entropy increased. b. Its entropy decreased. c. Its entropy remained constant. d. Work was converted to energy.

a. Its entropy increased.

Which of the following best describes the relationship between two systems in thermal equilibrium? a. No net energy is exchanged. b. The volumes are equal. c. The masses are equal. d. The velocity is zero.

a. No net energy is exchanged.

When a drop of ink mixes with water, what happens to the entropy of the system? a. The system's entropy increases, and the total entropy of the universe increases. b. The system's entropy decreases, and the total entropy of the universe increases. c. The system's entropy increases, and the total entropy of the universe decreases. d. The system's entropy decreases, and the total entropy of the universe decreases.

a. The system's entropy increases, and the total entropy of the universe increases.

Which is denser, ice at 0 degrees C or water at 4 degrees C? a. The water b. The ice c. They both have the same density.

a. The water

Which has the higher specific heat capacity, water or sand? a. Water b. Sand c. They both have the same specific heat capacity.

a. Water

Mix some 70°C water with some 40°C water and you'll get water at _____. a. a temperature depending on the masses (or volumes) of water b. 40°C c. 55°C d. 70°C

a. a temperature depending on the masses (or volumes) of water

Temperature is related mostly to the _____. a. average molecular kinetic energy in a substance b. total kinetic energy in something c. average energy in a substance d. total energy in something e. average kinetic energy of an object

a. average molecular kinetic energy in a substance

The use of fiberglass insulation in the outer walls of a building is intended to minimize heat transfer through what process? a. conduction b. radiation c. convection d. vaporization

a. conduction

If a volume of air is swept upward with no heat input or output, its temperature a. decreases. b. remains the same. c. increases.

a. decreases.

Which of the following terms describes a transfer of energy? a. heat b. internal energy c. temperature d. kinetic energy

a. heat

Which of the following is a way to improve the efficiency of a heat engine? a. increase Qh b. reduce Qh c. reduce Wnet d. increase Qc

a. increase Qh

When a volume of air is compressed and no heat enters or leaves, the air temperature will a. increase. b. remain unchanged. c. decrease.

a. increase.

Which thermodynamic process takes place at constant volume so that no work is done on or by the system? a. isovolumetric b. isobaric c. adiabatic d. isothermal

a. isovolumetric

When an iron ring is heated, the hole becomes _____. a. larger b. smaller c. neither smaller nor larger

a. larger

The fact that desert sand is very hot in the day and very cold at night is evidence that sand has a _____. a. low specific heat capacity b. high specific heat capacity

a. low specific heat capacity

Systems that are left alone tend to move toward a state of a. more entropy. b. less entropy. c. no entropy.

a. more entropy.

Entropy is closely related to the a. second law of thermodynamics. b. first law of thermodynamics. c. both of the above d. none of the above

a. second law of thermodynamics.

During a very cold winter, water pipes sometimes burst. The reason for this is _____. a. water expands when freezing b. water contracts when freezing c. the ground contracts when colder, pulling pipes apart d. the thawing process releases pressure on the pipes e. none of the above

a. water expands when freezing

Consider a gap cut into a metal ring. If the ring is heated, the gap becomes _____. a. wider b. narrower c. neither

a. wider

An ideal gas system undergoes an adiabatic process in which it expands and does 20 J of work on its environment. How much energy is transferred to the system as heat? a. -20 J b. 0 J c. 5 J d. 20 J

b. 0 J

80 joules of heat is added to a system that performs 55 Joules of work. The internal energy change of the system is a. 0 J. b. 25 J. c. 55 J. d. 135 J. e. none of the above.

b. 25 J.

If there is no temperature difference between a substance and its surroundings, what has occurred on the microscopic level? a. Energy has been transferred from lower-energy particles to higher-energy particles. b. Energy has been transferred from higher-energy particles to lower-energy particles. c. No energy has been transferred between the substance and its surroundings. d. Heat has been flowing back and forth.

b. Energy has been transferred from higher-energy particles to lower-energy particles.

A thermodynamic process occurs, and the entropy of a system decreases. What can be concluded about the entropy change of the environment? a. It decreases. b. It increases. c. It stays the same. d. It could increase or decrease, depending on the process.

b. It increases.

Which of the following is true during a phase change? a. Temperature increases. b. Temperature remains constant. c. Temperature decreases. d. There is no transfer of energy as heat.

b. Temperature remains constant.

If energy is transferred from a table to a block of ice moving across the table, which of the following statements is true? a. The table and the ice are at thermal equilibrium. b. The ice is cooler than the table. c. The ice is no longer 0°C. d. Energy is being transferred from the ice to the table.

b. The ice is cooler than the table.

Which releases the most energy, 100 grams of 100°C water cooling to 50°C, or 100 grams of iron at 100°C cooling to 50°C? (The specific heat of iron is 0.12 cal/g°C.) a. Iron b. Water c. both the same

b. Water

Which equation describes the net work done for a complete cycle of a heat engine? a. Wnet = Q - ΔU b. Wnet = Qh- Qc c. Wnet = Qc- Qh d. Wnet = PΔV

b. Wnet = Qh- Qc

When work is done by a system and no heat is added to it, the temperature of the system a. remains unchanged. b. decreases. c. increases.

b. decreases.

A bimetallic strip will bend when heated because _____. a. metals bend when heated b. each metal expands at different rates c. each side of the strip is at a different temperature d. metals contract when heated e. all of the above

b. each metal expands at different rates

How is energy transferred as heat always directed? a. from an object at low temperature to an object at high temperature b. from an object at high temperature to an object at low temperature c. from an object at low kinetic energy to an object at high kinetic energy d. from an object with higher mass to an object of lower mass

b. from an object at high temperature to an object at low temperature

The greater the difference in temperature between the input reservoir and output reservoir for a heat engine, the a. less the efficiency. b. greater the efficiency. c. neither—efficiency doesn't depend on temperature difference.

b. greater the efficiency.

Pull a closed plastic bag of dry air quickly down from a high elevation and the bag of air will become a. cooler. b. hotter. c. neither of the above.

b. hotter.

According to the first law of thermodynamics, the difference between energy transferred to or from a system as heat and energy transferred to or from a system by work is equivalent to which of the following? a. entropy change b. internal energy change c. volume change d. pressure change

b. internal energy change

A calorimeter is used to determine the specific heat capacity of a test metal. If the specific heat capacity of water is known, what quantities must be measured? a. metal volume, water volume, initial and final temperatures of metal and water b. metal mass, water mass, initial and final temperatures of metal and water c. metal mass, water mass, final temperature of metal and water d. metal mass, water mass, heat added to or removed from water and metal

b. metal mass, water mass, initial and final temperatures of metal and water

Ceramic automobile engines that operate at higher temperatures will be a. less efficient. b. more efficient. c. neither of the above.

b. more efficient.

The requirement that a heat engine must give up some energy at a lower temperature in order to do work corresponds to which law of thermodynamics? a. first b. second c. third d. No law of thermodynamics applies.

b. second

Two identical blocks of iron, one at 10 degrees C and the other at 20 degrees C, are put in contact. Suppose the cooler block cools to 5 degrees C and the warmer block warms to 25 degrees C. This would violate the a. first law of thermodynamics. b. second law of thermodynamics. c. both of the above d. none of the above

b. second law of thermodynamics.

During an isovolumetric process, which of the following does not change? a. temperature b. volume c. pressure d. internal energy

b. volume

While an ideal gas is doing positive work on its surroundings, which of the gas's quantities must be increasing? a. temperature b. volume c. pressure d. internal energy

b. volume

Running a refrigerator with its door open in a hot room makes the room a. cooler. b. warmer. c. none of the above.

b. warmer.

In an elastic collision between two ball bearings, kinetic energy is conserved. If there is no change in potential energy, which of the following is true? a. ΔU > 0 b. ΔU = 0 c. ΔU < 0 d. ΔU cannot be determined for this event.

b. ΔU = 0

A slice of bread contains about 4.19 *10^5 J of energy. If the specific heat capacity of a person is 4.19*10^3 J/kg*°C, by how many degrees Celsius would the temperature of a 70.0 kg person increase if all the energy in the bread were converted to heat? a. 2.25°C b. 1.86°C c. 1.43°C d. 1.00°C

c. 1.43°C

A container of water has its smallest volume at _____. a. -20 degrees C b. 0 degrees C c. 4 degrees C

c. 4 degrees C

Imagine you could observe the individual atoms that make up a piece of matter and that you observe the motion of the atoms becoming more orderly. What can you assume about the system? a. It is gaining thermal energy. b. Its entropy is increasing. c. Its entropy is decreasing. d. Positive work is being done on the system.

c. Its entropy is decreasing.

If two small beakers of water, one at 70°C and one at 80°C, are emptied into a large beaker, what is the final temperature of the water? a. The final temperature is less than 70°C. b. The final temperature is greater than 80°C. c. The final temperature is between 70°C and 80°C. d. The water temperature will fluctuate.

c. The final temperature is between 70°C and 80°C.

Which statement applies when all of the entropy changes in a process are taken into account? a. The increases in entropy are always less than the decreases. b. The increases in entropy are always equal to the decreases. c. The increases in entropy are always greater than the decreases. d. The increases in entropy can be greater or less than the decreases.

c. The increases in entropy are always greater than the decreases.

Air cools as it escapes from a diver's compressed air tank. What kind of process is this? a. isovolumetric b. isobaric c. adiabatic d. isothermal

c. adiabatic

Cool a sample of air from zero on the Celsius scale to near zero on the absolute scale and the air loses a. volume. b. pressure. c. both A and B d. neither A nor B

c. both A and B

When mechanical work is done on a system, there can be an increase in its a. temperature. b. internal energy. c. both of the above d. none of the above

c. both of the above

The energy content of a piece of food is normally determined by _____. a. eating the piece of food b. measuring the volume of the food c. burning the food d. none of the above

c. burning the food

Heat is the _____. a. average amount of energy per molecule contained in an object b. total amount of energy contained in an object c. energy transferred between objects because of a temperature difference d. amount of energy all the molecules have e. all of the above

c. energy transferred between objects because of a temperature difference

As a system becomes more disordered, entropy a. remains the same. b. decreases. c. increases.

c. increases.

Suppose the temperature of the input reservoir in a heat engine doesn't change. As the sink temperature is lowered, the efficiency of the engine a. stays the same. b. decreases. c. increases.

c. increases.

What three properties of a substance affect the amount of energy transferred as heat to or from the substance? a. volume, temperature change, specific heat capacity b. density, temperature change, specific heat capacity c. mass, temperature change, specific heat capacity d. mass, temperature change, latent heat

c. mass, temperature change, specific heat capacity

Internal energy is the _____. a. average amount of energy contained in an object b. amount of energy that is transferred from one object to another object c. total amount of energy contained in an object d. amount of kinetic energy all the molecules have e. all of the above

c. total amount of energy contained in an object

The reason fish live from year to year in ponds that freeze over in the winter is that _____. a. fish are cold-blooded and can stand being frozen and thawed b. fish swim so fast they keep the water from freezing under the surface c. water below the ice is 4 degrees above freezing d. fish hibernate during the winter e. none of the above

c. water below the ice is 4 degrees above freezing

How is conservation of internal energy expressed for a system during an isothermal process? a. Q = W = 0, so ΔU = 0 and Ui = U f b. Q = 0, so ΔU = -W c. ΔT = 0, so ΔU = 0; therefore, ΔU = Q - W = 0, or Q = W d. ΔV = 0, so PΔV = 0 and W = 0; therefore, ΔU = Q

c. ΔT = 0, so ΔU = 0; therefore, ΔU = Q - W = 0, or Q = W

A volume of air has a temperature of 0 degrees Celsius. An equal volume of air that is twice as hot has a temperature of about a. 0 degrees C. b. 2 degrees C. c. 100 degrees C. d. 273 degrees C. e. none of the above

d. 273 degrees C.

The ideal efficiency for a heat engine operating between temperatures of 2050 K and 310 K is a. 15%. b. 50%. c. 25%. d. 85%. e. none of the above.

d. 85%.

According to the second law of thermodynamics, which of the following statements about a heat engine operating in a complete cycle must be true? a. Heat from a high-temperature reservoir must be completely converted to work. b. Heat from a high-temperature reservoir equals the entropy increase. c. Heat from a high-temperature reservoir must be completely converted to internal energy. d. Heat from a high-temperature reservoir cannot be completely converted to work.

d. Heat from a high-temperature reservoir cannot be completely converted to work.

Which of the following is not a widely used temperature scale? a. Kelvin b. Fahrenheit c. Celsius d. Joule

d. Joule

Which of the following expands most when the temperature is lowered? a. Helium b. Iron c. Wood d. Water at 4 degrees C e. None of the above expands when the temperature is lowered.

d. Water at 4 degrees C

The first law of thermodynamics is a restatement of the a. Carnot cycle. b. law of heat addition. c. principle of entropy. d. conservation of energy. e. none of the above

d. conservation of energy.

In an isovolumetric process for an ideal gas, the system's change in the energy as heat is equivalent to a change in which of the following? a. temperature b. volume c. pressure d. internal energy

d. internal energy

What are the energies associated with atomic motion called? a. kinetic energy b. potential energy c. bond energy d. internal energy

d. internal energy

What thermodynamic process for an ideal gas system has an unchanging internal energy and a heat intake that corresponds to the value of the work done by the system? a. isovolumetric b. isobaric c. adiabatic d. isothermal

d. isothermal

An electrical power plant manages to transfer 88 percent of the heat produced in the burning of fossil fuel to convert water to steam. Of the heat carried by the steam, 40 percent is converted to the mechanical energy of the spinning turbine. Which best describes the overall efficiency of the heat-to-work conversion in the plant? a. greater than 88 percent b. 88 percent c. 40 percent d. less than 40 percent

d. less than 40 percent

Entropy measures a. temperature as volume increases. b. temperature as pressure increases. c. temperature at constant pressure. d. messiness. e. temperature at constant volume.

d. messiness.

How is conservation of internal energy expressed for a system during an isovolumetric process? a. Q = W = 0, so ΔU = 0 and Ui = U f b. Q = 0, so ΔU = -W c. ΔT = 0, so ΔU = 0; therefore, ΔU = Q - W = 0, or Q = W d. ΔV = 0, so PΔV = 0 and W = 0; therefore, ΔU= Q

d. ΔV = 0, so PΔV = 0 and W = 0; therefore, ΔU= Q