Description : For which of the following substances, the gas laws can be used with minimum error (a) dry steam (b) wet steam (c) saturated steam (d) superheated steam (e) steam at atmospheric pressure.
Last Answer : Answer : d
Description : Which is NOT a correct statement? A. A superheated vapor will not condense when small amount of heat re removed B. An ideal gas is a gas that is not a superheated vapor C. A saturated ... absorb as much heat as it can without vaporizing D. Water at 1 atm and room temperature is subcooled
Last Answer : An ideal gas is a gas that is not a superheated vapor
Description : __________________ is a vapor having a temperature higher than the saturation temperature corresponding to the existing pressure. a) Vapor b) Saturated Vapor c) Superheated Vapor d) Wet Vapor
Last Answer : Superheated Vapor
Description : ___________________ is a vapor at the saturation conditions (saturation temperature and saturation pressure). a) Vapor b) Saturated Vapor c) Superheated Vapor d) Wet Vapor
Last Answer : Saturated Vapor
Description : Superheated vapour behaves (a) exactly as gas (b) as steam (c) as ordinary vapour (d) approximately as a gas (e) as average of gas and vapour.
Description : Steam at 1000 lbf/ft^2 pressure and 300˚R has specific volume of 6.5 ft^3/lbm and a specific enthalpy of 9800 lbf-ft/lbm. Find the internal energy per pound mass of steam. A.2500 lbf-ft/lbm B.3300 lbf-ft/lbm C.5400 lbf-ft/lbm D.6900 lbf-ft/lbm Formula: h= u+ pV u= h– pV
Last Answer : 3300 lbf-ft/lbm
Description : A 10m^3 vessel initially contains 5 m^3 of liquid water and 5 m^3 of saturated water vapor at 100 kPa. Calculate the internal energy of the system using the steam table. A. 5 x10^5 kJ B. 8x10^5 kJ C. 1 ... 3 kJ/kg ug= 2506kJ/kg formula: Mvap = V vap/vg M liq = Vliq/ vƒ u =uƒM liq + ug M vap
Last Answer : 2 x10^6 kJ
Description : When water exists in the liquid phase and is not about to vaporize, it is considered as _____liquid. A. Saturated B. Compressed or subcooled C. Superheated D. Unsaturated
Last Answer : Compressed or subcooled
Description : _________________ is a combination of saturated vapor and saturated liquid. a) Vapor b) Saturated Vapor c) Superheated Vapor d) Wet Vapor
Last Answer : Wet Vapor
Description : _________________ is the name given to a gaseous phase that is in contact with the liquid phase, or that is in the vicinity of a state where some of it might be condensed. a) Vapor b) Saturated Vapor c) Superheated Vapor d) Wet Vapor
Last Answer : Vapor
Description : A vapor that is not about to condense is called _____ vapor. A. Saturated B. Compressed or subcooled C. Superheated D. Unsaturated
Last Answer : Superheated
Description : A vapor that is about to condense is called ______ vapor. A. Saturated B. Compressed or subcooled C. Superheated D. Unsaturated
Last Answer : Saturated
Description : A liquid that is about to vaporize is called ______ liquid. A. Saturated B. Compressed or subcooled C. Superheated D. Unsaturated
Description : If heat be exchanged in a reversible manner, which of the following property of the working substance will change accordingly (a) temperature (b) enthalpy (c) internal energy (d) entropy (e) all of the above.
Description : Change in enthalpy in a closed system is equal to heat transferred if the reversible process takes place at constant (a) pressure (b) temperature (c) volume (d) internal energy (e) entropy.
Last Answer : Answer : a
Description : Which of the following is the property of a system (a) pressure and temperature (b) internal energy (c) volume and density (d) enthalpy and entropy (e) all of the above.
Last Answer : Answer : e
Description : What happens to the internal energy of water at reference temperature where enthalpy is zero? a. Becomes negative b. Becomes positive c. Remains constant d. Cannot be defined
Last Answer : Becomes negative
Description : The thermodynamic difference between a Rankine cycle working with saturated steam and the Carnot cycle is that (a) carnot cycle can't work with saturated steam (b) heat is supplied to water at temperature ... heat at two places (d) rankine cycle is hypothetical (e) none of the above.
Last Answer : Answer : b
Description : Entropy is the measure of: a. The internal energy of a gas b. The heat capacity of a substance c. Randomness or disorder d. The change of enthalpy of a system
Last Answer : Randomness or disorder
Description : In an isothermal process, A. there is no change in temperature B. there is no change in enthalpy C. there is no change in internal energy D. all of these
Last Answer : Answer: D
Description : Total heat of a substance is also known as (a) internal energy (b) entropy (c) thermal capacity (d) enthalpy (e) thermal conductance.
Description : Properties of substances like pressure, temperature and density, in thermodynamic coordinates are (a) path functions (b) point functions (c) cyclic functions (d) real functions (e) thermodynamic functions.
Description : Which of the following occurs in a reversible polytrophic process? a. Enthalpy remains constant b. Internal energy does not change c. Some heat transfer occurs d. Entropy remains constant
Last Answer : Some heat transfer occurs
Description : What is the measure of the energy that is no longer available to perform useful work within the current environment? a. enthalpy b. entropy c. internal energy d. latent heat
Last Answer : entropy
Description : What is known as the total heat and heat content at various times in the history? a. enthalpy b. entropy c. internal energy d. latent heat
Last Answer : enthalpy
Description : Sum of the internal energy of a substance and the product of pressure and volume. a. Specific Heat b. Specific Gravity c. Isolated System d. Enthalpy
Last Answer : Enthalpy
Description : The sum of internal energy (U) and the product of pressure and volume (p.v) is known as A. workdone B. entropy C. enthalpy D. none of these
Last Answer : Answer: C
Description : According to first law of thermodynamics (a) work done by a system is equal to heat transferred by the system (b) total internal energy of a system during a process remains constant ( ... , enthalpy and entropy during a process remain constant (d) total energy of a system remains constant
Description : Which of the following is the other term used for enthalpy-entropy diagram? a. Enthalpy diagram b. Mollier diagram c. Steam diagram d. Entropy chart
Last Answer : Mollier diagram
Description : Steam is throttled to 0.1 MPa with 20 degrees of superheat. (a) What is the quality of throttled steam if its pressure is 0.75 MPa (b) What is the enthalpy of the process? a) 97.6%,2713 kJ/kg b) -97.6%, 2713 kJ/kg c) 87.6%,3713 kJ/kg d) -87.6%, 3713 kJ/kg
Last Answer : 97.6%,2713 kJ/kg
Description : _____________ is the difference between the actual temperature of superheated vapor and the saturation temperature for the existing pressure. a) Degrees of Superheat, °SH b) Degrees of Sub cooled, °SB c) Both a and b d) None of the above
Last Answer : Degrees of Superheat, °SH
Description : What refers to the pressure at which a pure substance changes phase at a given temperature? A. Equilibrium pressure B. Saturation pressure C. Superheated pressure D. Subcooled pressure
Last Answer : Saturation pressure
Description : What refers to the temperature at which a pure substance changes phase at a given pressure? A. Equilibrium temperature B. Saturation temperature C. Superheated temperature D. Subcooled temperature
Last Answer : Saturation temperature
Description : During throttling process (a) heat exchange does not take place (b) no work is done by expanding steam (c) there is no change of internal energy of steam (d) all of the above (e) entropy decreases.
Description : What is considered as the heat content of a system? A. Enthalpy B. Entropy C. Internal heat D. Molar heat
Description : Which law states that the internal energy of a gas is a function of temperature (a) Charles’ law (b) Joule’s law (c) Regnault’s law (d) Boyle’s law (e) there is no such law.
Description : A perfect gas at 27°C is heated at constant pressure till its volume is double. The final temperature is (a) 54°C (b) 327°C (c) 108°C (d) 654°C (e) 600°C
Description : According to Avogadro's Hypothesis (a) the molecular weights of all the perfect gases occupy the same volume under same conditions of pressure and temperature (b) the sum of partial pressure of ... gases have two values of specific heat (e) all systems can be regarded as closed systems.
Description : According to Gay-Lussac law for a perfect gas, the absolute pressure of given mass varies directly as (a) temperature (b) absolute (c) absolute temperature, if volume is kept constant ... , if temperature is kept constant (e) remains constant,if volume and temperature are kept constant.
Last Answer : Answer : c
Description : Which of the following variables controls the physical properties of a perfect gas (a) pressure (b) temperature (c) volume (d) all of the above (e) atomic mass.
Description : Which of the following can be regarded as gas so that gas laws could be applicable, within the commonly encountered temperature limits. (a) 02, N2, steam, C02 (b) Oz, N2, water vapour (c) S02, NH3, C02, moisture (d) 02, N2, H2, air (e) steam vapours, H2, C02.
Description : Change in enthalpy of a system is the heat supplied at (a) constant pressure (b) constant temperature (c) constant volume (d) constant entropy (e) N.T.P. condition.
Description : If value of n is infinitely large in a polytropic process pV” = C, then the process is known as constant (a) volume (b) pressure (c) temperature (d) enthalpy (e) entropy
Description : Which of the following parameters is constant for a mole for most of the gases at a given temperature and pressure (a) enthalpy (b) volume (c) mass (d) entropy (e) specific volume.
Description : Find the change in internal energy of 5 lb. of oxygen gas when the temperature changes from 100 ˚F to 120 ˚F. CV = 0.157 BTU/lbm-˚R A.14.7 BTU B.15.7 BTU C. 16.8 BTU D. 15.9 BTU Formula: U= mcv T
Last Answer : 15.7 BTU
Description : An adiabatic process is one in which A.no heat enters or leaves the gas B.the temperature of the gas changes C.the change in internal energy is equal to the mechanical workdone D.all of the above
Description : For a perfect gas, according to Boyle’s law (where p = Absolute pressure, v = Volume, and T = Absolute temperature) A. p v = constant, if T is kept constant B. v/T = constant, if p is kept constant C. p/T = constant, if v is kept constant D. T/p = constant, if v is kept constant
Last Answer : Answer: A
Description : The absolute pressure of a given mass of a perfect gas varies inversely as its volume, when the temperature remains constant. This statement is known as Charles’ law. A. Yes B. No
Last Answer : Answer: B
Description : According to Gay-Lussac law, the absolute pressure of a given mass of a perfect gas varies __________ as its absolute temperature, when the volume remains constant. A. directly B. indirectly
Description : Saturated steam at a pressure of 25 kg/cm2is throttled to attain 5 kg/cm2. Then the outcoming steam will be (A) Wet (B) Saturated (C) Superheated (D) None of these
Last Answer : C) Superheated