Description : Twenty grams of oxygen gas are compressed at a constant temperature of 30 ˚C to 5%of their original volume. What work is done on the system. A.824 cal B.924 cal C.944 cal D.1124 cal Formula: W = -mRTln (V2/V1) Where R = (1.98 cal/gmole·K) (32 g/gmole)
Last Answer : 1124 cal
Description : The volume of a given amount of water _________ as the temperature decreases from 4˚C to 0˚C. a. decreases b. increases c. remains constant d. none of the above
Last Answer : increases
Description : There are 1.36 kg of gas, for which R = 377 J/kg.k and k = 1.25, that undergo a nonflow constant volume process from p1 = 551.6 kPa and t1 = 60°C to p2 = 1655 kPa. During the process the gas is internally stirred and ... (Formula: T2= T1p2/ p1) a. 999 K b. 888 K c. 456 K d. One of the above
Last Answer : 999 K
Description : During the adiabatic process, which of the following is the change in entropy? a. zero b. greater than zero c. less than zero d. infinity
Last Answer : zero
Description : The change that the system that undergoes from one equilibrium state to another is known as a. oath b. process c. enthalpy change d. entropy change
Last Answer : process
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 : A state occurs in isentropic process a. The change in entropy is 0 b. The change in entropy is 1 c. The change in enthalpy is 0 d. The change in enthalpy is 1
Last Answer : The change in entropy is 0
Description : Regardless of the process, the change in enthalpy firm moles of ideal gas is a. Heat b. Enthalpy c. Entropy d. Density
Last Answer : Heat
Description : During adiabatic, internally reversible process, what is true about the change in entropy? A. It is temperature-dependent B. It is always greater than zero C. It is always zero D. It is always less than zero
Last Answer : It is always zero
Description : 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 . This statement is known as: A. Entropy ... B. Entropy change of a system C. Entropy balance relation D. Third law of thermodynamics
Last Answer : Entropy balance relation
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.
Last Answer : Answer : d
Description : If a system after undergoing a series of processes, returns to the initial state then (a) process is thermodynamically in equilibrium (b) process is executed in closed system cycle (c) its entropy will ... sum of heat and work transfer will be zero (e) no work will be done by the system.
Description : Change in internal energy 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 : c
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 : For reversible adiabatic process, change in entropy is (a) maximum (b) minimum (c) zero (d) unpredictable (e) negative
Description : A cylinder contains oxygen at a pressure of 10 atm and a temperature of 300 K. The volume of the cylinder is 10 liters. What is the mass of the oxygen in grams? Molecular weight (MW) of oxygen is 32 g/mole? a. 125.02 b. 130.08 c. 135.05 d. 120.04
Last Answer : 130.08 {(10atm)(10)(32)/(0.0821) (300K)}
Description : When a solid melts, a. the temperature of the substance increases. b. the temperature of the substance decreases. c. heat leaves the substance. d. heat enters the substance.
Last Answer : heat enters the substance.
Description : A perfect gas has a value of R= 319.2 J/ kf.K and k= 1.26. If 120 kJ are added to 2.27 kf\g of this gas at constant pressure when the initial temp is 32.2°C? Find T2. a. 339.4 K b. 449.4 K c. 559.4K d. 669.4K formula: cp = kR/ k-1 Q= mcp(T2-T1)
Last Answer : 339.4 K
Description : For a certain gas R = 320 J/kg.K and cv= 0.84kJ/kg.K. Find k? a. 1.36 b. 1.37 c. 1.38 d. 1.39 formula: k= R / cv+1
Last Answer : 1.38
Description : In the above problem, find the potential energy of the mass with respect to datum. (Formula: P = mgz/k ) a. 4875 j b. 0.51 j c. 0.46 j d. None of the above
Last Answer : 4875 j
Description : Specific heat of air at constant pressure is equal to (a) 0.17 (b) 0.21 (c) 0.24 (d) 1.0 (e) 1.41
Description : A thermodynamic process in which entropy is conserved a. isentropic b. adiabatic c. isothermal d. polytropic
Last Answer : isentropic
Description : A process during which entropy remains constant is called ______ process A. Isometric B. Isochoric C. Isobaric D. Isentropic
Last Answer : Isentropic
Description : The entropy __________ in an irreversible cyclic process. A. remains constant B. decreases C. increases
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 : 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 : 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 : What refers to the heat needed to change the temperature of the substances without changing its phases? a. Latent heat b. Sensible heat c. Specific heat d. entropy
Last Answer : Sensible heat
Description : A ______ is a flow in which the gas flow is adiabatic and frictionless and entropy change is zero. A. Isentropic flow B. Isobaric flow C. Steady flow D. Uniform flow
Last Answer : Isentropic flow
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 : First law of thermodynamics (a) enables to determine change in internal energy of the system (b) does not help to predict whether the system will or not undergo a change (c) does not enable ... entropy (d) provides relationship between heat, work and internal energy (e) all of the above.
Last Answer : Answer : e
Description : Entropy change depends on (a) heat transfer (b) mass transfer (c) change of temperature (d) thermodynamic state (e) change of pressure and volume.
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 : 3.0 lbm of air are contained at 25 psia and 100 ˚F. Given that Rair = 53.35 ft-lbf/lbm- ˚F, what is the volume of the container? A.10.7 ft^3 B.14.7 ft^3 C.15 ft^3 D.24.9 ft^3 Formula: use the ideal gas law pV = mRT T = (100 +460) ˚R V = mRT/p
Last Answer : 24.9 ft^3
Description : When liquid water is converted to steam at 100˚C, the entropy of water a. increases b. decreases c. remains the same d. none of the above
Description : The entropy of water at 0°C is assumed to be A. 1 B. 0 C. -1 D. 10
Last Answer : Answer: B
Description : The compression ratio for Diesel engines is A. 3 to 6 B. 5 to 8 C. 15 to 20 D. 20 to 30
Description : The compression ratio for petrol engines is A.3 to 6 B.5 to 8 C.15 to 20 D.20 to 30
Description : Utilizing the answer to the previous problem, estimate the overall or average increase in temperature ( ΔT) of the concrete roof from the energy absorbed from the sun during a12hour day. Assume that all of the radiation absorbed goes into ... °C b. 8.9°C c. 9.9°C d. 10.9°C formula: ΔQ = m c ΔT
Last Answer : 7.9 °C
Description : The value of gas constant (R) in S. I. units is A. 0.287 J/kgK B. 2.87 J/kgK C. 28.7 J/kgK D. 287 J/kgK
Last Answer : Answer: D
Description : Which of the following laws of thermodynamic which leads to the definition of entropy? a. First law b. Second law c. Third law d. Law of conservation of energy
Last Answer : Second law
Description : A temperature scale whose zero point is absolute zero, the temperature of “0” entropy at which all molecular motion stops. a. Celsius b. Fahrenheit c. Kelvin d. Rankine
Last Answer : Kelvin
Description : As temperature goes to “0”, the entropy approaches a constant a. Zeroth Law of Thermodynamics b. First Law of Thermodynamics c. Second Law of Thermodynamics d. Third Law of Thermodynamics
Last Answer : Third Law of Thermodynamics
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 : Which law that states “Entropy of all perfect crystalline solids is zero at absolute zero temperature”? a. Zeroth law of thermodynamics b. First law of thermodynamics c. Second law of thermodynamics d. Third law of thermodynamics
Last Answer : Third law of thermodynamics
Description : Who coined the word Entropy? a. Rudolf Clausius b. Kelvin c. Gabriel Volks d. Rudolf Diesel
Last Answer : Rudolf Clausius
Description : What is the area under the curve on a temperature –entropy diagram? a. Heat b. work c. entropy d. volume
Description : What is the entropy of a pure substance at a temperature of absolute zero? a. unity b. zero c. infinity d. undefined
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