Chapter 2 Flashcards
(20 cards)
An example of a closed non-flow system:
a. Water heated inside a boiler
b. steam driving a turbine
c. cooling medium in heat exchanger
A
The law of conversion of mass and energy may be applied to
a. depends on type of system
b. system only
c. surroundings only
d. system and surroundings
D
Energy form that is never possessed by the body
Heat
Mechanical
A system of butane, propane, and pentane exists in a vapor-liquid equilibrium. How many internal properties must be fixed to define the state of system
3
(2 - 2 phases + 3 species)
A rock on a cliff and a pond of water are at the same temperature and surroundings. The rock originally with potential energy equal to 4kJ falls into the water and both ultimately come again into the same thermal equilibrium with the surroundings. Which of the following represents the changes in energy that the rock and pond has undergone
a. ∆U = 4,∆Ek = 0,∆Ep = - 4,Q = 0,W = 0
b. ∆U = -4,∆Ek = -4,∆Ep = - 4,Q = -4,W= 0
c. ∆U = 0,∆Ek = 0,∆Ep = - 4,Q = -4,W = 0
C
A fluid transported through a pipe is considered as what type of system
Open Steady Flow
If a gas is confined in a piston - cylinder device and is allowed to expand irreversibly in total vacuum, then
a. ∆U=0
b. Q=0
c. W=0
C
Closed systems undergoing the same changes of state by different processes will have
Equal (Q + W)’s
Which of the following is not a thermodynamic state function
a. Q
b. H
c. V
d. KE
A
If a body releases 10 Btu of heat, what is the change in total energy of the universe
0 Btu
In the compression or expansion work for a fluid contained in a piston cylinder assembly, dW = Pdv. P is always the?
holding pressure
For an ideal gas contained in a rigid vessel undergoing a change of state with negligible kinetic and potential energy changes, then
a. Q = ∆U
b. Q = W
c. Q = 0
d. Q = ∆H
A
Form of energy which is a function of temperature
Internal Energy
A process is considered reversible if the net driving force is
infinitesimal
If temperature and volume of a fluid in a closed non-flow system is constant then all of the following for the system is true, EXCEPT
a. ∆U = 0
b. ∆H = 0
c. Q = 0
d. W = 0
C (not sure)
Work done to the system may be directly converted to, Except
a. Potential Energy
b. Internal Energy
c. Thermal Energy
d. Kinetic Energy
C
To define the final state of three different gases mixed together, how many properties must be given?
4
If a system produces 1 Btu of work, what is the change in energy of the surroundings?
+1 Btu
Explanation:
Produces means done by the system so Wsystem = Wsurr
W = -W
- 1 Btu = -(-1Btu)
1 Btu = Wsurr
The law of conservation of mass and energy may be applied to
a. Depends on type of system
b. System only
c. Surroundings only
d. System and surroundings
D
Which of the following properties of a closed system depends on the path taken by the process?
a. T
b. U
c. KE
d. W
D
