A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of 3 7 . 0 ∘ C . As it does so, it absorbs 208 J of heat. The values of q and w for the process will be (R = 8.314 J/mol K) (ln7.5 = 2.01)

q = + 2 0 8 J , w ⁡ = - 2 0 8 J

q = + 2 0 8 J , w ⁡ = + 2 0 8 J

q = - 2 0 8 J , w ⁡ = - 2 0 8 J

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Important Questions on Thermodynamics

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

The work done during combustion of

9 \times 10^{- 2}

kg

of ethane,

C_{2} H_{6} (g)

300 K

is (Given

R = 8 .314 {JK}^{- 1} {mol}^{- 1}

, atomic mass

C = 12, H = 1

)

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

The above

P - V

diagram represents the thermodynamic cycle of an engine, operating with an ideal mono-atomic gas. The amount of heat, extracted from the source in a single cycle, is:

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

A system consisting of 1 mol of an ideal gas undergoes a reversible process,

A \to B \to C \to A

(schematically indicated in the figure below). If the temperature at the starting point A is 300 K and the work done in the process

B \to C

is 1 L atm, the heat exchanged in the entire process in L atm is

Question Image

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

A gas undergoes change from state

A

to state

B

. In this process, the heat absorbed and work done by the gas is

5 J and 8 J

, respectively. Now gas is brought back to

A

by another process during which

3 J

of heat is evolved. In this reverse process of

B to A

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

The qualitative sketches I, II and III given below show the variation of surface tension with molar concentration of three different aqueous solutions of KCl,

C H_{3} O H

and

C H_{3} {(C H_{2})}_{11} O S O_{3}^{-} N a^{+}

at room temperature. The correct assignment of the sketches is -

Question Image

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

X g

of ice at

0^{o} C

is added to 340g of water at

20^{o} C

. The final temperature of the resultant mixture is

5^{o} C

. The value of

X

(in g) is closest to

[Heat of fusion of ice

= 333 J / g

; Specific heat of water

= 4.184 J / g . K

]

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constant temperature of

37 . 0^{\circ} C

. As it does so, it absorbs 208 J of heat. The values of q and w for the process will be
(R = 8.314 J/mol K) (ln7.5 = 2.01)

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

The volume vs. temperature graph of 1 mole of an ideal gas is given below

Question Image

The pressure of the gas (in atm) at

X, Y

and

Z,

respectively, are

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

An ideal gas undergoes isothermal compression from

5 m^{3}

1 m^{3}

against a constant external pressure of

4 N m^{- 2}

. The heat released in this process is

24 J {mol}^{- 1} K^{- 1}

and is used to increase the pressure of

1

mole of

Al

. The temperature of

Al

increases by:

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

The combination of plots which does not represent isothermal expansion of an ideal gas is

$(A)$ Question Image

$(B)$

$(C)$

$(D)$

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

An ideal gas undergoes isothermal expansion at constant pressure. During the process:

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

n

moles of an ideal gas undergoes a process

A \to B

as shown in the figure. The maximum temperature of the gas during the process will be:
Question Image

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

For the isothermal reversible expansion of an ideal gas

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

Calculate the work done during compression of

2

mol of an ideal gas from a volume of

1 m^{3}

10

{dm}^{3}

300 K

against a pressure of

100 kPa

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

A gas is allowed to expand in a well-insulated container against a constant external pressure of

2.5 atm

from an initial volume of

2.50 L

to a final volume of

4.50 L .

The change in internal energy

ΔU

of the gas in joules will be

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

The molar enthalpy change for

H_{2} O (l) ⇌ H_{2} O (g)

373 K

and

1 atm

40 kJ / mol

. Assuming ideal behaviour, the internal energy change for vaporization of

1 mol

of water at

373 K

and

1 atm

kJ {mol}^{- 1}

is:

MEDIUM

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

The three processes in a thermodynamic cycle shown in the figure are : Process $1 \to 2$ is isothermal; Process $2 \to 3$ is isochoric (volume remains constant); Process $1 \to 3$ is adiabatic.

Question Image

The total work done by the ideal gas in this cycle is, $10 J .$ The internal energy decreases by, $20 J$ in the isochoric process. The work done by the gas in the adiabatic process is, $- 20 J$ . The heat added to the system in the isothermal process is

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

A reversible cyclic process for an ideal gas is shown below. Here,

P, V, a n d T

are pressure, volume and temperature, respectively. The thermodynamic parameters

q, w, H a n d U

are heat, work, enthalpy and internal energy, respectively.

Question Image

The correct option(s) is (are)

EASY

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

A piece of ice falls from a height

h

so that it melts completely. Only one-quarter of the heat produced is absorbed by the ice and all energy of ice gets converted into heat during its fall. The value of

h

is:
(Latent heat of ice is

3.4 \times 10^{5} {J kg}^{- 1}

and

g = 10 {N kg}^{- 1}

)

HARD

Physics>Heat and Thermodynamics>Thermodynamics>Zeroth Law of Thermodynamics

A closed tank has two compartments A and B, both filled with oxygen (assumed to be ideal gas). The partition separating the two compartments is fixed and is a perfect heat insulator (Figure

1

). If the old partition is replaced by a new partition which can slide and conduct heat but does not allow the gas to leak across (Figure

2

), the volume (in

m^{3}

) of the compartment A after the system attains equilibrium is

\frac{20}{x} m^{3}

. Write the value of

x

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Important Questions on Thermodynamics

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