MAE 241 Introduction to Thermodynamics Exam 1 Practice

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• What is the energy carried by a flowing fluid across a control-volume boundary per unit mass, including flow work, in the steady-flow energy equation?
• The portion of the internal energy of a system associated with the kinetic energies of the molecules is called?
• A substance that is not about to vaporize is best described as which?
• The speed of sound in an ideal gas is a = sqrt(γ R T). Which expression correctly represents a?
• Which term is used to describe a process that proceeds with infinitesimal steps keeping the system near equilibrium?
• Why is h = u + p v useful in open-system energy balances?
• For a saturated steam–water mixture, the statement 'When x = 0.5, the mixture enthalpy is halfway between hf and hg' is true or false?
• The form of energy that can be converted to mechanical work completely and directly by an ideal mechanical device
• For an ideal gas, the internal energy depends on temperature only.
• Which term describes a system in which the pressure is uniform throughout?
• During a saturated phase change at constant pressure, which properties change and by how much?
• What is the enthalpy change of an ideal gas when the temperature changes by ΔT?
• Magnitudes assigned to dimensions are called:
• In the limit n → 1 for a polytropic process, the work is W = …?
• Which mode of heat transfer occurs through emission of electromagnetic waves?
• In a piston-cylinder device, when the gas expands, the boundary work W is
• The ratio of the mechanical energy increase of the fluid to the mechanical energy output defines which efficiency?
• Which expression correctly defines gage pressure?
• Which term describes a process in which a system exchanges no heat with its surroundings?
• Which term is volume per unit mass?
• The Carnot efficiency represents the maximum possible efficiency for a heat engine operating between two reservoirs.
• Efficiency is defined as the ratio of
• In a multi-phase system, which equilibrium describes no net change in phase masses and compositions?
• A reversible adiabatic process is isentropic.
• Which term describes a system whose properties are fixed?
• What is the expression for boundary work for a piston-cylinder device?
• What term describes the temperature at which a pure substance changes phase at a given pressure?
• Which term describes the weight of a unit volume of a substance (density times gravity)?
• The term for the surface that separates a system from its surroundings
• Which description correctly identifies a solid?
• Which expression represents the first law for energy transfers in a simple system?
• Which statement correctly identifies the state of a simple compressible system under the state postulate?
• For an ideal gas, which expression gives the entropy change Δs between states 1 and 2 in terms of T and either V or P?
• Ws = 1/2 k (Δx)^2 represents the energy stored in a spring.
• Explain the concept of flow work in your own words. Which term represents it in the energy balance?
• For an ideal gas undergoing an isentropic process, how are P2/P1 and T2/T1 related?
• Power is defined as work per unit time.
• For an ideal gas, express h and u in terms of T and Cp, Cv.
• Which term denotes the condition where solid, liquid, and gas phases exist in equilibrium?
• Which term describes the pressure at which a pure substance changes phase at a given temperature?
• Which term is the energy that can be completely transformed into mechanical work by an ideal device?
• How can you determine qualitatively whether a process is isentropic?
• Which term is defined as a state of balance?
• What term describes the ratio of vapor mass to the total mass of a two-phase mixture?
• What is the expression for the efficiency of a reversible heat engine in terms of heat transfer?
• Which mechanism describes energy transfer through particle interactions within a substance due to temperature differences?
• For a saturated steam–water mixture, how is the mixture enthalpy computed from x, hf, and hg?
• Meters, kilograms, seconds, kelvin, etc are examples of:
• The ratio of electric power output to mechanical power input defines which efficiency?
• Which term best describes properties that do not depend on the amount of material in the system?
• Define latent heat and give typical values for water at 1 atm.
• Any change that a system undergoes from one equilibrium to another is called a
• In a two-phase mixture, what quantity represents the fraction of the mixture that is vapor?
• Is boundary work zero for a rigid-walled container?
• What does the Zeroth Law imply about temperature?
• Which thermodynamic quantity h is defined by h = u + Pv?
• State the relation for internal energy change for an ideal gas with temperature change: ΔU = m Cv ΔT.
• Mass, length, time, temperature, etc are defined as which concept?
• In a saturated steam–water mixture, the mixture enthalpy when x = 0 is which value?
• For a polytropic process with n ≠ 1, the boundary work is given by which expression?
• Combustion efficiency is defined as
• State the relation between heat transfer at constant pressure and enthalpy change for a pure substance.
• The term for the standard set of units that includes meters, kilograms, seconds, and kelvin
• Which phase has molecules at relatively fixed positions?
• Real or imaginary surface that separates the system from the surroundings
• If a process occurs at constant pressure and the system cannot exchange heat with the surroundings, is Q zero? What about W?
• The volume of a fluid flowing through a cross section per unit time is called?
• Provide typical latent heats for water at 1 atm: fusion and vaporization.
• Which energy transfer mode is described by energy moving from a solid surface to adjacent moving fluid?
• Which statement best describes shaft work?
• If Cp − Cv = R, which statement about gamma is true?
• A system with fixed mass and no mass crossing its boundary is called a
• In an isochoric process, which property remains constant?
• Which term refers to a vapor that is about to condense?
• A substance that has a fixed chemical composition throughout is called which?
• For a rigid, adiabatic process in a closed system, what is ΔU?
• What process describes the transition from a solid directly to a vapor?
• Which instrument measures small and moderate pressure differences?
• For a static fluid, the hydrostatic relation for pressure with depth is Pabs = Patm + rho g h. Which statement is true?
• In a saturated mixture, as quality x increases from 0 to 1, how does the mixture specific volume v behave?
• One of two forms of energy interactions associated with a closed system; an energy interaction is heat transfer if its driving force is a temperature change
• During a saturated phase change at constant pressure, h_fg represents what?
• Which statement expresses the conservation of energy principle?
• Which are examples of extensive properties?
• How would you compute the heat required to raise the temperature of a liquid with mass m and specific heat Cp?
• At a given pressure, h_f and h_g represent the enthalpies of which states?
• An isothermal process occurs at constant temperature.
• Which type of property is independent of the system’s mass?
• The energy a system possesses due to its motion relative to a reference frame is called?
• Which concept describes a system with a fixed amount of mass and energy?
• Boundary work is best described as the work associated with
• For an ideal gas, how do you compute the specific volume v from P and T?
• Which term describes a system state with no net chemical change and no reaction progress?
• Which statement describes the composition of the total energy change in a closed system?
• For an ideal gas, what is the relationship between gamma and specific heats?
• Cp and Cv definitions via derivatives of enthalpy and internal energy with respect to temperature are given by which expressions?
• Which list best describes the typical problem-solving steps used in thermodynamics analyses?
• Which term refers to a region where mass and energy can flow across boundaries, typically associated with devices like turbines?
• Which term describes a property that can be varied while the other property remains constant?
• The state postulate applies to a simple compressible system only when there are no electrical, magnetic, gravitational, motion, or surface tension effects.
• Which term describes constant temperature throughout an entire system, as stated in the zeroth law?
• For liquids, how is enthalpy approximately related to temperature, given small compressibility?
• Which statement is NOT a valid classification for system properties?
• In a saturated steam–water mixture, the quality x represents the mass fraction of which phase?
• In a steady, adiabatic, inviscid flow through a nozzle or diffuser, which relationship between enthalpy and velocity holds (neglecting elevation changes)?
• General expression for W for a polytropic process with n ≠ 1, and for the special case n = 1 (isothermal).
• Which term describes a process that proceeds in such a small manner that the system remains infinitesimally close to equilibrium at all times?
• Which term describes constant chemical composition of a system, with no chemical reactions?
• The concept used to express quantities without changing dimensions, as a relative factor
• For an isothermal process of an ideal gas with P = (m R T)/V, which expression represents the work done during a transition from V1 to V2?
• If a liquid and its vapor are in equilibrium at a given pressure and temperature, they are in which type of equilibrium?
• Which phase is characterized by groups of molecules moving about each other?
• The energy transfer associated with a force acting through a distance is called
• The statement 'Energy is a thermodynamic property' aligns with which law?
• Which quantity is a state function?
• A process in which the temperature remains constant is called
• Write the mass-flow rate and energy balance for a steady-flow control volume with one inlet and one outlet.
• How is a continuum defined?
• Define quality x for a saturated mixture.
• Which point marks the end of the liquid-vapor coexistence curve, where liquid and vapor become indistinguishable?
• Which of the following is an example of an intensive property?
• Fixed amount of mass, no mass can cross its boundary describes which type of system?
• Which statement expresses the Zeroth Law of Thermodynamics?
• For an ideal gas, the enthalpy depends only on temperature.
• Turbine efficiency is defined as the ratio of mechanical energy output to which quantity?
• The ratio of mechanical power output to electric power input defines which efficiency?
• The amount of mass flowing through a cross section per unit time is called?
• What term describes extensive properties per unit mass?
• The ratio of the mechanical energy output to the mechanical energy decrease of the fluid defines which efficiency?
• What are the typical room-temperature values for air: Cp, Cv, γ, and R?
• Which properties depend on the size of the system?
• If the absolute pressure equals atmospheric pressure, what is the gage pressure?
• The energy form that can be converted entirely to work by an ideal device is called
• Which term refers to the conditions of a system when all properties are fixed?
• Which term represents mass per unit volume?
• The quantity dw/dt is commonly referred to as
• What is the sign convention for shaft work Wdot in a compressor if Wdot is defined as work done by the system?
• Which pair of equations correctly describes the adiabatic reversible relations for an ideal gas?
• Limit of W for polytropic as n→1.
• In an ideal gas, if the temperature doubles and pressure remains the same, how does volume change?
• Pump efficiency is defined as the ratio of the mechanical energy increase of the fluid to which quantity?
• The general steady-flow energy equation (SFEE) for a control volume with mass and energy flow, including Q̇ and Ẇ, is:
• Which statement best defines a steady flow process?
• What is the key distinction between a closed system and a control volume regarding mass?
• A liquid that is about to vaporize is best described as which?
• The work required to raise a body to a higher elevation is equal to which energy change?
• Which term describes energy content of a system due to microscopic states and motions?
• Which term describes a two-phase mixture that is at the boiling point for a given pressure?
• Heating value of a fuel is defined as the amount of heat released when a unit amount of fuel is completely burned and the combustion products are cooled to room temperature.
• Which phase is characterized by molecules moving about at random?
• Which instrument is used to measure small and moderate pressure differences?
• Which instrument is used to measure atmospheric pressure directly?
• Motor efficiency is defined as the ratio of which quantities?
• Which of the following is a path function?
• A process in which the specific volume remains constant is called
• Which term describes constant pressure throughout an entire system?
• A process in which the pressure remains constant is called
• Which term describes when the mass of each phase in a system reaches a balance and stays there?
• Which thermodynamic property is defined as the heat content of a system at constant pressure and equals u + Pv?
• An ideal-gas process is isothermal; what is Δu for the gas?
• Equal to one and are unitless describes which concept?
• A simple compressible system is completely specified by how many independent intensive properties?
• Using the sign convention δQ into the system and δW by the system, what is the first law for a closed system?
• What is the series of states through which a system passes during a process called?
• Which term represents energy transfer due to a temperature difference across a boundary, independent of mass flow?
• Which term is defined as the ratio of a substance's density to the density of a reference substance at the same temperature?
• Express the enthalpy of a saturated mixture using h_f, h_g, and quality x.
• Vacuum pressure refers to pressures below atmospheric pressure. Which expression correctly defines it?
• The units of h_f and h_g are what?
• Lower heating value is defined as the heating value when the water in the combustion gases is a vapor
• Which of the following is a state function?
• Which statement differentiates the lower and higher heating values?
• How does irreversibility affect the actual efficiency relative to the Carnot efficiency?
• For a steady-flow control volume, if the mass inside does not accumulate (steady state), what is dM_cv/dt?
• Mechanical efficiency is defined as
• During an adiabatic expansion of an ideal gas, what happens to the temperature?
• Which term describes the boundary of a control volume that can be real or imaginary?
• For an ideal gas, what is the relation between Cp, Cv, and R?
• Absolute pressure is defined as the actual pressure at a location measured relative to what reference?
• What term describes the state at which the liquid and vapor phases coexist in equilibrium?
• The first law of thermodynamics for a closed system can be written as:
• If the initial and final states of a system are identical, the process is called a
• Which term describes the boundary that encloses a region for mass and energy balance calculations and can be real or imaginary?
• What term is defined as any characteristic of a system?
• Gage pressure is defined as the difference between which two pressures?
• What is the total energy of a system?
• In a fluid at rest, how does pressure vary with depth and horizontal position?
• In an isochoric process for an ideal gas, if heat is added, what are W and ΔU?
• Energy has quality as well as quantity is associated with which law?
• A 2 kg sample of water is heated from 25°C to 75°C at constant volume. Use Cv ≈ 4.18 kJ/kg·K to compute Q.
• In a quasi-equilibrium piston-cylinder process, the boundary-work is given by which expression?
• In the control volume energy balance, which term represents energy carried by entering mass flows?
• Which term is defined as the sum of all microscopic forms of energy?
• Region outside a system describes which term?
• Wsh = 2π n T represents shaft work per revolution.
• Which term describes a substance existing in three phases in equilibrium (solid, liquid, and gas)?
• The work required to accelerate a body is equal to the change in which energy?
• In an adiabatic process, the heat transfer to the system is zero
• Which option correctly states the ideal gas law per unit mass and the definition of the specific volume v?
• The flow work included in the enthalpy term h for a flowing fluid is equal to which product?
• Path functions depend on the process path, whereas state (point) functions depend only on the state.
• If the volume remains constant and the mass doubles, what happens to the specific volume v = V/m?
• Which expression correctly expresses the entropy change of an ideal gas using temperature and pressure?
• Energy due to elevation in a gravitational field is called?
• Higher heating value is defined as the heating value when the water in the combustion gases is completely condensed and thus the heat of vaporization is also recovered
• What is the Carnot efficiency for a reversible heat engine operating between a hot reservoir at temperature Th and a cold reservoir at Tc?
• Boundary work occurs when the system boundary moves, causing a change in
• Which term best captures energy cannot be created or destroyed, only transformed within an isolated system?
• Is heat transfer included in the steady-flow energy equation, and if so, how is Qdot applied?
• A process in which the initial and final states are identical is called a
• Which term describes a vapor that exists at a temperature above its boiling point for the current pressure?
• The internal energy associated with the phase of a system is called?
• In a saturated steam–water mixture, what is h when x = 1?
• For an ideal gas, the speed of sound a = sqrt(γ R T). If temperature is doubled, how does a change?
• Which term describes a vapor that is not about to condense?
• What do you call the real or imaginary boundary of a control volume?
• Generator efficiency is defined as which ratio?
• In the steady-flow energy equation, where does the shaft work term Ẇ_out appear when the system does work on surroundings?
• Which device is commonly used to measure atmospheric pressure directly?
• In a saturated liquid-vapor mixture, the mixture specific volume v is expressed as which linear combination of v_f and v_g with quality x?
• Which of the following is a state function?
• Temperature, pressure, density, and specific volume are examples of what kind of property?
• In an isothermal process, which property remains constant?
• Which term is the energy associated with the phase of a system?