Questions 641–650 of 1772. Imported answers require independent review unless marked reviewed.

Topic practice 1772 questionsPage 65 of 178

Question 94

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An insulated rigid closed tank of 2 m

internal volume contains saturated liquid-vapor mixture of water at 200 °C. The quality of the mixture is 0.75. The mass of the mixture in the tank is __________ kg (rounded off to one decimal place). Use the following data for water: At 200 °C:

m

/kg,

m

/kg,

m

/kg

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Question 95

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A rigid closed tank contains 2 kg of an ideal gas at 500 kPa and 350 K. A valve is opened, and half of the mass of the gas is allowed to escape. Then the valve is closed. If the final pressure in the tank is 300 kPa, the final temperature in the tank is __________ K (in integer).

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Question 96

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Air at 400 K and 200 kPa is heated at constant pressure to 600 K. Assuming that the internal energy is a function of temperature only, the magnitude of change in internal energy during this process is __________ kJ/kmol (rounded off to one decimal place). Use the following data: Molar specific heat of air at constant volume

(kJ/kmol-K)

where T is temperature in K,

kJ/kmol-K,

kJ/kmol-K

and

kJ/kmol-K

.

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Question 97

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XE-EMCQ2 marksNeeds review
A rigid closed tank having a volume of 2 m

contains 0.1 m

of saturated liquid water and 1.9 m

of saturated water vapor at 100 kPa. Heat is transferred to the tank until the final tank pressure reaches 2 MPa. Following data for water is given: At 100 kPa:

m

/kg,

m

/kg,

kJ/kg,

kJ/kg; At 2 MPa:

m

/kg,

m

/kg,

kJ/kg,

kJ/kg. The magnitude of heat transfer in this process is
Your answerChoose one option.

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Question 98

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An ideal Diesel cycle has a compression ratio of 20 and cut-off ratio of 1.5. At the beginning of the compression stroke, air is at 100 kPa, 300 K. Use the cold-air-standard assumptions with property value

kJ/kg-K. Assume

. For this cycle, the net work output per unit mass is
Your answerChoose one option.

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Question 99

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A 5 kg metal block (

kJ/kg-K) at 373 K is submerged into 10 kg of water (

kJ/kg-K) at 293 K in an insulated rigid container without spilling. Assuming thermal equilibrium is reached, the approximate entropy change of the universe is
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Question 100

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Match the following:
Thermodynamic function/equation
Expression
A1 Helmholtz function (a)
B1

A2 Gibbs function (g)
B2

A3 T-ds equation
B3

A4 Clapeyron-Clausius equation
B4

Your answerChoose one option.

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Question 101

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A piston-cylinder device initially contains 1 m

of air at 200 kPa and 25 °C. Air expands at constant pressure while a heater of 250 W is switched on for 10 minutes. There is a heat loss of 4 kJ during this process. Assuming air as an ideal gas, the final temperature of air is ______ °C (rounded off to one decimal place).
Use the following data for air:

kJ/kg-K,

kJ/kg-K

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Question 102

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Steam at 2 MPa and 300 °C steadily enters a nozzle of inlet diameter of 20 cm. Steam leaves the nozzle with a velocity of 300 m/s. The mass flow rate of steam through the nozzle is 10 kg/s. Assume no work interaction and no change in potential energy. If the heat loss from the nozzle per kg of steam is 3 kJ, the exit enthalpy per kg of steam is ______ kJ (rounded off to nearest integer).
Use the following data for steam:
At 2 MPa and 300 °C:

m

/kg,

kJ/kg

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Question 103

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XE-ENAT2 marksNeeds review
A rigid tank of 2 m

internal volume contains 5 kg of water as a saturated liquid-vapor mixture at 400 kPa. Half of the mass of the saturated liquid in the tank is drained-off while maintaining constant pressure of 400 kPa in the tank. The final quality of the mixture remaining in the tank is ______ (rounded off to two decimal places).
Use the following data for water:
At 400 kPa:

m

/kg,

m

/kg,

m

/kg

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