In a thermodynamic process, the internal energy of a system in a container with adiabatic walls decreases by 800 J. Which statement is correct?
a. The system lost 800 J by heat transfer to its surroundings.
b. The system gained 800 J by heat transfer from its surroundings.
c. The system performed 800 J of work on its surroundings.
d. The surroundings performed 800 J of work on the system.
e. The 800 J of work done by the system was equal to the 800 J of heat transferred to the system from its surroundings.
[Ques. 2] Water at room temperature, 20C, is pumped into a reactor core where it is converted to steam at 200C. How much heat (in J) is transferred to each kilogram of water in this process? (csteam = 2 010 J/kg/C; Lsteam = 2.26 103 J/g; 1 cal = 4.186 J.)
a. 3.35 105
b. 7.53 105
c. 2.67 106
d. 2.80 106
e. 3.01 106
[Ques. 3] How much heat, in joules, is required to convert 1.00 kg of ice at 0C into steam at 100C? (Lice = 333 J/g; Lsteam = 2.26 103 J/g.)
a. 3.35 105
b. 4.19 105
c. 2.36 106
d. 2.69 106
e. 3.01 106
[Ques. 4] Which statement below regarding the First Law of Thermodynamics is most correct?
a. A system can do work externally only if its internal energy decreases.
b. The internal energy of a system that interacts with its environment must change.
c. No matter what other interactions take place, the internal energy must change if a system undergoes a heat transfer.
d. The only changes that can occur in the internal energy of a system are those produced by non-mechanical forces.
e. The internal energy of a system cannot change if the heat transferred to the system is equal to the work done by the system.
[Ques. 5] For an astronaut working outside a spaceship, the greatest loss of heat would occur by means of
a. conduction.
b. convection.
c. radiation.
d. conduction and convection.
e. conduction and radiation.
[Ques. 6] In which process will the internal energy of the system NOT change?
a. An adiabatic expansion of an ideal gas.
b. An isothermal compression of an ideal gas.
c. An isobaric expansion of an ideal gas.
d. The freezing of a quantity of liquid at its melting point.
e. The evaporation of a quantity of a liquid at its boiling point.
[Ques. 7] Which of the following statements is correct?
a. You only need to know the amount of thermal energy a body contains to calculate its temperature.
b. The temperature of a body is directly proportional to the amount of work the body has performed.
c. The quantity of thermal energy exchanged by two bodies in contact is inversely proportional to the difference in their temperatures.
d. The quantity of thermal energy exchanged by two bodies in contact is directly proportional to the difference in their temperatures.
e. Different amounts of thermal energy are transferred between two bodies in contact if different temperature scales are used to measure the temperature difference between the bodies.
[Ques. 8] If an object feels cold to the touch, the only statement that you can make that must be correct is that
a. the object has a smaller coefficient of thermal conductivity than your hand.
b. the volume of the object will increase while it is in contact with your hand.
c. the object contains less thermal energy than your hand.
d. the object is at a lower temperature than your hand.
e. the object cannot be a liquid.
[Ques. 9] Two kilograms of water at 100C is converted to steam at 1 atm. Find the change in internal energy (in J). (Lv = 2.26 106 J/kg.)
a. 2.1 104
b. 4.5 106
c. 3.4 105
d. 4.2 106
e. 2.1 106
[Ques. 10] Two kilograms of water at 100C is converted to steam at 1 atm. Find the work done (in J). (The density of steam at 100C is 0.598 kg/m3.)
a. 3.4 105
b. 1.2 105
c. 4.6 104
d. 2.1 104
e. 3.4 104
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