Thermodynamics 2 (RCARDS) Flashcards by Pauline Peralta

Amount of heat removed removed from the cooled space in BTS’s for 1 watt-hour of electricity consumed.

Energy Efficiency Rating

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Which of the ff. is mathematical representation of Charle’s Law?

A. V1/T1 = V2/T2
B. V1/V2 = P2/P1
C. V1/V2 = ‘(P2)/’(P1)
D. V1/T2 = V2/T1

V1/T1 = V2/T2

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Which is NOT a correct statement?
A. An ideal gas is a gas that is not a superheated vapor.
B. Water at 1atm and room temperature is subcooled.
C. A saturated liquid can absorb as much heat as it can without vaporizing.
D. A superheated vapor will not condense when small amount of heat are removed.

An ideal gas is a gas that is not a superheated vapor.

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Carnot cycle is the best known reversible cycle. It was first proposed in what year?
A. 1842
B. 1824
C. 1832
D. 1834

1824

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It states that “Entropy can be created but it cannot be destroyed.”

Second Law of Thermodynamics

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Absorptivity of a Black Body.

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What is the latent heat of vaporization of water at 1 atm?

2257.1 kJ/kg

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What refers to the pressure at which a pure substance changes phase at a given temperature?

Saturation Pressure

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Who proposed carnot cycle?

Sadi Carnot

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What is defined as the direct conversion of a substance from solid to the vapor state or vice versa without passing the liquid state?

Sublimation

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A device that violates the first law of thermodynamics is called

A. Perpetual-motion machine of the first kind
B. Unique machine of the first kind
C. Ambiguous machine of the first kind
D. Universal machine of the first kind

Perpetual-motion machine of the first kind

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Ratio of net electrical power output to the rate of fuel energy input.

Overall Efficiency

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The ratio of work output to the energy input.

Thermal Efficiency

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What is the latent heat of fusion of water at 1 atm?

333.7 kJ/kg

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Which statement of the second law states that “No heat engine can have a thermal efficiency of 100%”?

Kelvin-Planck Statement

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is expressed as follows: It is impossible to construct a device that operates in a cycle and produces no effect other than the transfer of heat from a lower-temperature body to a higher-temperature body.

Clausius Statement

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is expressed as follows: It is impossible for any device that operates on a cycle to receive heat from a single reservoir and produce a net amount of work. This statement can also be expressed as no heat engine can have a thermal efficiency of 100 percent, or as for a power plant to operate, the working fluid must exchange heat with the environment as well as the furnace.

Kelvin-Planck statement of the second law of thermodynamics

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A process during which entropy remains constant

Isentropic

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For heat engine operating between two temperatures (T1 > T2), What is the the maximum efficiency attainable?

A. Eff = 1 - (T2/T1)
B. Eff = 1 - (T1/T2)
C. Eff = T1 - T2
D. Eff = 1 - (T2/T1)²

Eff = 1 - (T2/T1)

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Water Boils when
A. Its saturated vapor pressure equals to the atmospheric pressure
B. Its temperature reaches 212° Celsius
C. Its vapor pressure is 1 gram per sq. cm
D. Its vapor pressure equals 76 cm of mercury

Its saturated vapor pressure equals to the atmospheric pressure

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What is the amount of heat needed to turn 1kg of the substance at its boiling point from the liquid to the gaseous state?

Heat of vaporization

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What predicts the approx. molar specific heat at high temperatures from the atomic weight?

Law of Dulong and Petit

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What are the assumptions of the kinetic gas?
A. All of the above
B. The volume of the gas molecules is negligible compared to the volume of the gas.
C. The molecules behave like hard spheres.
D. Gas molecules do not attract each other.

All of the above

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Universal Gas Constant = ______ J/Kmol

8.3145

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The gas constant of a certain gas is the ratio of:

Universal Gas Constant to Molar mass

Heating of the earth's atmosphere not caused by direct sunlight but by infrared light radiated by the surface and absorbed mainly by atmospheric carbon dioxide.

Greenhouse Effect

An ideal gas whose specific heats are constant is called

Perfect Gas

What is constant for a substant that is considered incompressible?

Specific Volume of Density

Ratio of the useful heat extracted to heating value.

Combustion Efficiency

The ratio of the change in temperature to the change in pressure when a real gas is throttled.

Joule-Thompson Coefficient

1 British Thermal Unit (BTU) = ___ J

1055

States that "Thermal efficiencies of all reversible heat engine operating between the same two reservoirs are the same and that no heat engine is more efficient than a reversible one operating between the same two reservoirs."

Carnot Principle

States that "The net mass transfers to or from a system during a process is equal to the net change in the total mass of the system during that process."

Conservation of Mass Principle

A form of mechanical work which is related with the expansion and compression of substances.

Boundary Work

The rate of thermal radiation emitter per unit area of a body.

Emissive Power

What is the amount of heat needed to turn 1 kg of the substance at its melting point from solid to liquid state?

Heat of Fusion

States that "It is impossible to build a device that operates in a cycle and produces no effect other than the transfer of heat from a lower-temperature body to a higher-temperature body." A. Third Law of Thermodynamics B. Second Law of Thermodynamics C. Zeroth Law of Thermodynamics D. First Law of Thermodynamics

Second Law of Thermodynamics

If there is no heat transferred during the process, it is called a _____ process.

adiabatic

States that "The net change in the total energy of the system during a process is equal to the difference between the total energy entering and the total energy leaving the system during that process." A. Second Law of Thermodynamics B. Conservation of Energy Principle C. Third Law of Thermodynamics D. Conservation of Mass Principle

Conservation of Energy Principle

During adiabatic, internally reversible process what is true about change in entropy?

It is always zero

States that "it is impossible to operate an engine operating in a cycle that will have no other effect than to extract heat from a reservoir and turn it into an equivalent amount of work." A. Third Law of Thermodynamics B. Second Law of Thermodynamics C. Zeroth Law of Thermodynamics D. First Law of Thermodynamics

Second Law of Thermodynamics

Thermal Radiation is an electromagnetic radiation with wavelengths in ____ range.

0.1 - 100 micrometer

An adiabatic process in which there is no change in system enthalpy but for which there is a significant decrease in pressure is called _______.

Throttling Process

"Adiabatic" comes from Greek "Adiabatos" which means

Not to be Passed

A device that violates the second law of thermodynamics is called ________. A. Universal machine of the second kind B. Unique machine of the second kind C. Perpetual-motion machine of the second kind D. Ambiguous machine of the second kind

Perpetual-motion machine of the second kind

Isentropic Process implies: A. Irreversible adiabatic process B. Externally reversible, adiabatic process C. Internally reversible, adiabatic process D. Reversible adiabatic process

Internally reversible, adiabatic process

The ratio of the mass of vapor to the total mass of the mixture is called _____. A. Quality B. Vapor Ratio C. Vapor Content D. Vapor Index

Quality

What is a body that emits a constant emissivity regardless of the wavelength?

Gray Body

Which of the ff. is STP (Standard Temperature and Pressure) A. 0 degrees Celsius and one atmosphere B. 32 degree Fahrenheit and zero pressure C. 0 degree Kelvin and one atmosphere D. 0 degree Fahrenheit and zero pressure

0 degrees Celsius and one atmosphere

Which of the following is TRUE for ideal gas but not real gas? A. No attractive forces exists between the molecule of a gas B. PV = nRT C. An increase in temperature causes an increase in the kinetic energy of the gas D. The total volume of molecules on a gas is nearly the same as the volume of the gas as a whole.

PV = nRT

SI unit of specific heat capacity

J/kg×K but sometimes they say J/kg×C

Carnot cycle is composed of ____ reversible processes

What is a measure of the ability of a material to conduct heat?

Thermal conductivity

What refers to the amount of energy absorbed or released during a phase-change process?

Latent Heat

Equation of State refers to any equation that relates the _____ of the substance.

Pressure, Temperature and Specific Volume

A device that violates either the first law of thermodynamics or the second law of thermodynamics is known as _________. A. Ambiguous machine B. Unique machine C. Universal machine D. Perpetual-motion machine

Perpetual-motion machine

The amount of heat required to raise the temperature of 1 pound of water by 1°F is called ______.

BTU

Ein - Eout = ∆Esystem is known as

Energy Balance

Which of the ff. is the Ideal Gas Law?

PV = nRT

What is the value of the work done for a closed, reversible isometric system?

Zero

States that "For any two bodies in thermal equilibrium, the ratios of emissive power to the absorptivity are equal."

Kirchoff's radiation law

Emissivity of Black Body

A reversible adiabatic process is necessarily isentropic but an isentropic process is not necessarily reversible adiabatic process

True

What statement of the second law of thermodynamics states that "It is impossible to build a device that operates in a cycle and produces no effect other than the transfer of heat from a lower-body temperature to a higher-body temperature.?"

Clausius Statement

How does adiabatic Process compare to an isentropic process?

Both heat transfer = 0; isentropic is reversible

What law states that, the total volume of a mixture of non-reacting gases is equal to the sum of the partial volumes.

Amagat's Law

The entropy change of a system during a process is equal to the net entropy transfer through the system boundary and the entropy generated within the system.

Entropy balance relation

Carnot cycle is composed of _______ processes

2 isothermal and 2 adiabatic or **2 isothermal and 2 isentropic (for ideal reversible carnot cycle)**

Heat engine that operates on the reversible Carnot cycle?

Carnot Heat engine

The amount of heat required to raise the temperature of 1 kg of water through 1°C is called ___.

Kilocalorie

States that "One energy form can be converted without loss onto another form."

Joule's Law

Enthalpy comes from greek "enthalphen" which means _____.

Heat

What law predicts the dew point of moisture in the fuel gas?

Dalton's Law

In the process of radiation, energy is carried by electromagnetic waves. What is the speed of electromagnetic waves?

186,000 miles/second

Entropy is transferred by _______.

Heat

What is considered as a perfect absorber as well as perfect emitter?

Black

The highest efficiency of heat engine operating between the two thermal energy reservoirs at temperature limit?

Carnot Efficiency

Which of the ff. is formula for thermal resistance?

Thickness of Material / Thermal Conductivity of Material

Thermal Efficiency is the ratio of:

Network Output to Total Heat Input

What refers to the point at which the saturated liquid and saturated vapor states are the same or identical?

Critical Point

What law provides absolute reference point for the determination of entropy?

Third Law of Thermodynamics

The Coefficient of Performance (CoP) is the ratio between the:

Absorbed Heat and Work Required

Transfer of energy from the more energetic particles of a substance to the adjacent less energetic ones as a result of interaction between particles

Conduction

How is heat transferred? A. Radiation B. Conduction C. All of the above D. Convection

All of the above

The low temperature reservoir of the heat reservoirs is known as ________.

Sink Reservoir

What is defined as the energy required raising the temperature of a unit mass of a substance by one degree

Specific Heat

In the equation PV = RT, the constant of proportionality R is known as ______.

Gas Constant

Specific Heat Capacity of Water = ___ J / kg ⋅ °C

**4185 according to pinoybix** or 4184 *but according to khan academy it is 4184 J/kg⋅K* and **Chatgpt says both are correct because it is specific heat**

Transfer of energy between a solid surface and the adjacent fluid that is in motion.

Convection

A ______ is a flow in which the gas flow is adiabatic and frictionless and entropy change is zero

Isentropic flow

Transfer of energy due to the emission of electromagnetic waves or photons.

Radiation

It states that "The entropy of a pure crystalline substance at absolute zero temperature is zero."

Third Law of Thermodynamics

What remains constant during a steady flow process?

Mass and energy content of the control volume

The mass of one mole of a substance in grams is known as ________.

Molar Mass

What refers to the minimum temperature at which combustion can be sustained?

Ignition Temperature

Which one is the correct relation between Energy Efficiency Ratio (EER) and Coefficient of Performance (CoP)

EER = 3.42 CoP

At constant temperature, the volume of a gas is inversely proportional to the pressure. A. Gay-Lussac Law B. Charle's Law C. Ideal Gas Law D. Boyle's Law

Boyle's Law

At same temperatures, the radiation emitted by all real surfaces is _____ the radiation emitted by a black body

Less than

The ___ of a substance is the amount of heat that must be added or removed from a unit mass of the substance to change its temperature by one degree

Specific Heat Capacity

Which is NOT a characteristic of emissivity? A. it is independent with the surface condition of the material B. It is low with highly polished metal C. It is high with most nonmetals D. It is directly proportional to temperature

it is independent with the surface condition of the material

Sometimes known as "Fourth-Power Law"

Stefan-Boltzmann Law

Considering one mole of any gas, the equation of state of ideal gases is simply the ______ law.

Avogadro's