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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Assertion: Two metallic spheres of same size, one of copper and the other of aluminum, heated to the same temperature, will cool at the same rate when they are suspended in the same enclosure.

Reason: The rate of cooling of a body is directly proportional to the excess of temperature of the body over the surroundings.

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Important Questions on Thermodynamics

EASY

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>Thermodynamics>Zeroth Law of Thermodynamics

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

MEDIUM

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>Thermodynamics>Zeroth Law of Thermodynamics

For the isothermal reversible expansion of an ideal gas

EASY

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Chemistry>Physical Chemistry>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

Important Questions on Thermodynamics

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