Thermo Concepts Ref: Indiabix, ARC

Question 1

Which law is the basis for the manufacture of thermometers?

Answer 1

Zeroth Law of Thermodynamics

Question 2

How many degrees of freedom has each of the following systems?
14. Liquid water in equilibrium with its vapor

Answer 2

one

Question 3

Liquid water in equilibrium with a mixture of water vapor and nitrogen.

Answer 3

two

Question 4

A liquid solution of alcohol in water in equilibrium with its vapor.

Answer 4

two

Question 5

Energy is added to the water as work but is extracted from the water
as heat was performed by

Answer 5

joule

Question 6

These properties depend on the current state of the system and not
on how the system reaches that state.

Answer 6

state functions

Question 7

Which of the following statement is correct?
a. The standard heat of formation of an element is negative.
b. Since △H = △U + △PV and can never be equal to △U.
c. Q and W are state functions.
d. Q + W is a state function.

Answer 7

Q + W is a state function.

Question 8

The amount of heat absorbed when CO2 gas reacts with a solid CaO
to form solid CaCO3 is measured in a bomb calorimeter at constant
volume. The data obtained give a direct measure of

Answer 8

△U

Question 9

For a constant pressure reversible process, the enthalpy (∆H)
change of the system is

Answer 9

. ∫CpdT

Question 10

Cv is given by

Answer 10

(∂U/ ∂T)v

Question 11

Equation which relates pressure, volume, and temperature of a
gas is called

Answer 11

Equation of state

Question 12

The equation, PV = nRT is best obeyed by gases at

Answer 12

low pressure and high temperature

Question 13

Compressibility factor of a gas is

Answer 13

unity, if it follows PV = nRT

Question 14

Cp – Cv = R is valid for

Answer 14

ideal gases

Question 15

For monoatomic gases, Cp / Cv equals

Answer 15

1.67

Question 16

Isobaric process means a constant

Answer 16

pressure process

Question 17

For an isothermal process the internal energy of a gas

Answer 17

remains unchanged

Question 18

In an adiabatic process

Answer 18

heat transfer is zero

Question 19

From PVn = C, when n = 0, the process is

Answer 19

isobaric

Question 20

From PVn = C, the process is isochoric if n equals

Answer 20

∞

Question 21

A solid is transformed into vapor without going through the liquid
phase at

Answer 21

a. below triple point c. triple point

Question 22

Determine whether water is compressed liquid, superheated
vapor, saturated liquid, saturated vapor, or a mixture of saturated
liquid and saturated vapor, in each case. If the state is determined
to be a mixture, determine the quality.
(i) At 10 MPa and an entropy of 3.3 kJ/kg-K
(ii) At 320 0C and 5.6 MPa
(iii) With specific volume of 0.10 m3
/kg at 1 MPa
a. subcooled, superheated, mixture (0.50)
b. mixture (0.40), superheated, subcooled
c. superheated, mixture (0.60), subcooled
d. subcooled, mixture (0.30), superheated

Answer 22

subcooled, superheated, mixture (0.50)

Question 23

Work output of turbine is __ the work input to the pump

Answer 23

greater than

Question 24

The efficiency of Carnot cycle is ___ the efficiency of Rankine

Answer 24

greater than

Question 25

The losses in condenser are

Answer 25

small

Question 26

Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.

Answer 26

ISOTHERMAL

Question 27

Internal energy change of a system over one complete cycle in a cyclic process is

Answer 27

Zero

Question 28

Heating of water under atmospheric pressure is an __________ process.

Answer 28

Isobaric

Question 29

Van Laar equation deals with the activity co-efficients in

Answer 29

binary solutions

Question 30

High __________ is an undesirable property for a good refrigerant.

Answer 30

Viscosity

Question 31

Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the

Answer 31

low pressure and low temperature

Question 32

Entropy is a measure of the __________ of a system.

Answer 32

Disorder

Question 33

A chemical reaction will occur spontaneously at constant pressure and temperature, if the free energy is

Answer 33

Negative

Question 34

Fundamental principle of refrigeration is based on the __________ law of thermodynamics.

Answer 34

Second

Question 35

A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect ?

Answer 35

Carnot refrigeration cycle

Question 36

A refrigerator may be termed as a

Answer 36

Heat pump

Question 37

Entropy of an ideal gas depends upon its

Answer 37

Pressure and temperature

Question 38

Isobaric process means a constant process.

Answer 38

Pressure

Question 39

No work is done by the system, when a reaction occurs at constant

Answer 39

Volume

Question 40

If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the

Answer 40

Clayperon-Claussius equation

Question 41

Equilibrium constant decreases as the temperature

Answer 41

increases, for an exothermic reaction.

Question 42

Compressibility factor for almost all the gases are approximately same at the same

Answer 42

reduced pressure and reduced temperature.

Question 43

Free energy change at equilibrium is

Answer 43

Zero

Question 44

The temperature at which both liquid and gas phases are identical, is called the __________ point

Answer 44

Critical

Question 45

Any substance above its critical temperature exists as

Answer 45

Gas

Question 46

Isentropic process means a constant __________ process.

Answer 46

Entropy

Question 47

In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when

Answer 47

n=1

Question 48

A liquid under pressure greater than its vapour pressure for the temperature involved is called a __________ liquid.

Answer 48

Subcooled

Question 49

At absolute zero temperature, all substances have the same

Answer 49

heat capacity

Question 50

Grams of butane (C4H10) formed by the liquefaction of 448 litres of the gas (measured at (STP) would be

Answer 50

1160 - using PVN/rt N=58 V= 448 L ~ 0.448 m3 r= 8.314 K= 273.15 P= 101325