Exam 1 MC questions from HW

1. At a given state, all properties of a system have fixed values 2. In an equilibrium state, there are no unbalanced potentials

1. At a given state, all properties of a system have fixed values 2. In an equilibrium state, there are no unbalanced potentials 3. at a given state, all the properties of a system have fixed values except pressure and temperature 4. For a system in a given state, if one property changes value, the state will remain unchanged. 5. A system is able to maintain a given state even if values of multiple properties change.

Compressed liquid Saturated liquid Saturated liquid-vapor mixture Saturated vapor Superheated vapor

A substance initially exists as a compressed liquid at a pressure below the critical point. It is heated at constant pressure until it becomes superheated vapor. Put the following phases in the order from top to bottom that they would occur in the process. Saturated liquid Superheated vapor Saturated liquid-vapor mixture Compressed liquid Saturated vapor

thermodynamic cycle

A system is said to have undergone a __________ if it returns to its initial state at the end of the process

pressure

An isobaric process is a process during which ____________ remains constant

A property

Any characteristic of a system is called ________.

lower

At a given pressure, a substance in the saturated vapor phase will be at a ________ temperature than a superheated vapor

lower

Compressed liquid has ___________ temperature than saturated liquid at the same pressure

4

Consider the following example, A liquid is heated at constant pressure until it exists as a gas. At which of the following states would it be considered a saturated liquid-vapor mixture 1. All of the mass is liquid and the temperature has reached the boiling point. If any more heat is added, the subastance will start to vaporize. 2. All of the mass is liquid and it is not about to vaporize 3. All of the mass is in vapor phase and the substance is at its boiling point. If any heat were lost, the substance would start to condense 4. The substance is at the boiling point and both liquid and vapor phases are present. 5. All of the mass is in the vapor phase and if heat were lost, the temperature of the vapor would decrease.

Stay the same

During a process, if the state of the system does not change, the system energy will __________

output, input

Efficiency can be expressed in terms of the desired ________ divided by the required _________-

1,3,4

Energy transfer is involved in each of the following systems. Select the one either produces work or generates heat (all that apply) 1. a rotating shaft 2. water heated in a tub 3. a gas turbine 4. a rising piston 5. boiling water on a gas stove

internal, pressure, volume

Enthalpy, represented by the symbol h, is a property that combines ________ energy and product of _______ and specific _______

Unit mass

Extensive properties per __________ are called specific properties

Positive: Heat transfer into the system, Work done by the system Negative: Heat transfer out of the system, Work done to the system

Following the formal sign convention, please match the heat and work interactions with their appropriate signs (Positive or Negative) 1. Heat transfer into the system 2. Work done by the system 3. Heat transfer out of the system 4. Work done to the system

become halved

For an ideal gas under a constant temperature, if the pressure is doubled, the volume of the gas will ___________.

1,4,5

From the following list, which can be classified as pure substances? 1. a tank with liquid nitrogen 2. a glass of tea with ice 3. a mixture of air and water 4. a liquid vapor mixture of ammonia 5. a glass of ice water

0.79

Given the density of water at 1000 kg/m^3. If the density of a substance is 790 kg/m^3, what is the specific gravity

is approximately uniform throughout the system at each moment in time

If the gas in a piston-cylinder device undergoes a quasi-equilibrium compression, the pressure in a system _________________

remains the same

In a steady-flow process, the mass within the control volume _________

0W, 500W, -500W

In a well-insulated room, a 500W electric heater is used to provide space heating to the air in the room. If the control volume of the system includes the electric heater only, please determine respective charges of total energy, work, and heat transfer

500W, 0W, 500W

In a well-insulated room, a 500W electric heater is used to provide space heating to the air in the room. If the control volume of the system includes the room air only, please determine the respective rate changes of total energy, work, and heat transfer

Gas E, Z=0.2

Knowing the compressibility factor of the following gases, which gas's behavior below deviates the most from idea gas behavior? 1. Gas C, Z=1 2. Gas Z= 0.2 3. Gas D, Z=0.8 4. Gas B, Z=1.2 5. Gas A, Z=1.5

sublimation line

On a P-T diagram, the line separating solid and vapor phases is called the ________

saturated mixture

On a T-v diagram, the region under the dome area between the saturated liquid and saturated vapor lines is known as the _________ region

saturated, saturated

On a T-v diagram, the saturated liquid states can be connected by a line called the _______ liquid line, and the saturated vapor states can be connected by the _______ vapor line

1,3

Select all of the following statements that are true 1. as pressure increases, the saturation temperature of a substance increases. 2. at a given pressure, the temperature of a saturated vapor is usually greater than that of a saturated liquid 3. at a higher pressures, the difference in specific volume between saturated liquids and vapors of the same pressure decreases 4. At a given pressure in the super heated region, the specific volume decreases as temperature increase

1,4

Select all of the following statements that are true regarding the critical point. 1. The saturated vapor state is identical to the saturated liquid state 2. all three phases (solid, liquid, gas) are present 3. above the critical temperature, the substance is always considered a compressed liquid 4. At pressures above the critical pressure, there is no distinct phase change process

Pressure, Temperature, Specific volume

Select all the properties that apply: An equation of state is defined as any equation that relates that ________,_________, and _________ of a substance specific heat pressure temperature specific volume mass

1,2,5

Select the statements below that best express the 1st law of thermodynamics 1. The change in total energy during an adiabatic process must be equal to the net work input 2. Energy can neither be created nor destroyed. 3. Heat flows in the direction of decreasing temperature 4. energy has quality as well as quantity 5. energy is conserved.

superheated vapor

System A and system B contain the same substance. System A is a saturated vapor and is at the same temperature as system B. If system B has a lower pressure than A, what phase is system B in?

zeroth

System A is a thermometer. Systems A,B, and C are not in contact with one another but all have the same temperature. It can be stated that systems B and C are in thermal equilibrium because of the ____ law of thermodynamics

superheated vapor

System a and b contain the same substance. if system A is a saturated vapor, and has the same pressure as system B, but system B has a higher enthalpy value than A, what phase is system B in?

False

T/F: A rigid tank containing ionized gases kept under the influence of a magnetic field is a simple, compressible system

True

T/F: Specifications of two independent intensive properties in a single compressible system is sufficient to define a state

False

T/F: The weight of a system is an intensive property.

latent

The amount of energy absorbed or released during a phase change process is called the _________ energy

current

The electrical power equals to the square of the ________ multiplying the resistance

potential, current

The electrical power is defined by the product of the _____________ difference and the __________

potential energy

The energy that a system possesses as a result of its elevation in a gravitational field is called_________

5

The following statement would not describe the saturated liquid 1. it is about to vaporize 2. it refers to a point on a t-v diagram 3. any heat will cause some of the liquid to vaporize 4. it's still considered a liquid 5. It's about to condense

triple

The point at which solid, liquid, and vapor coexist in equilibrium is called the ________ point

sensible

The portion of the internal energy of a system associated with the kinetic energies of the molecules is called the ______ energy

torque, rotational

The power transmitted by a shaft is proportional to the __________ and the _________ speed

459.67

The rankine scale of temperature equals the Fahrenheit scale plus ___________.

critical

The reduced pressure and reduced temperature Pr and Tr are temperature and pressure normalized with respect to their _________ counterparts

path

The series of states through which a system passes during a process is called the ____

56.52kW

The torque applied to the shaft of a car is 180 Nm and the shaft rotates at a rate of 3000 rpm. What is the power transmitted through the shaft

3, 5

There are two requirments for a boundary work interaction between a system and its surrounding to exist. Please select the two correct answers 1. there must be an internal force, not external force, applied within the system's boundary 2. the boundary must be insulated 3. the boundary must move 4. The boundary must be imaginary 5. There must be a force acting on the boundary

temperature

Two bodies that have reached thermal equilibrium will have the same ____________

compressed liquid

Water in a tank is at the pressure of 5.5 MPa and temperature 260 C. The saturation pressure at the same temperature is 4.69 MPa. What is the phase of water?

Since the tank is sealed, mass is not allowed in or out of the system. Since the system is closed, the control mass approach should be used for thermodynamic analysis

What device is not suitable for using a control volume (open system) in the thermodynamic analysis of the system?

1

Which of the following best defines a solid? 1. The molecules are arranged in a three-dimensional pattern that is repeated throughout 2. The substance has a fixed volume that is not affected by changes in pressure. 3. The molecules of the substance are free to move and translate with respect to one another 4. The molecules donut move

Sensible energy, latent energy, and nuclear energy

Which of the following energy forms of a system are microscopic? 1. potential energy of a system 2. nuclear energy 3. electrical energy 4. sensible energy 5. latent energy

1,2,4,

Which of the following statements are true regarding gas? 1. Molecules move about at random in the gas phase. 2. it must release a large amount of energy before it can condense 3. intermolecular bonds are strongest in gases and weakest in solids 4. the molecules are far apart from each other, and a molecule order is non-existent 5. in a gas, the molecules are arranged in lattice position.

hf

enthalpy of saturated liquid

hg

enthalpy of saturated vapor

hfg

enthalpy of vaporization

Linear proportional

for linear elastic springs, the displacement of the spring is _______ to the force of applied

quality

the ______ is the mass of the vapor divided by the total mass of a saturated mixture.

Pressure and Temperature

the density of a substance is most likely dependent on _____________ (2 things)

pressure

the saturation temperature of a substance is affected by which of the following properties? - pressure - mass - volume