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

MEDIUM

Earn 100

Differentiate between the reversible and irreversible process on the basis of entropy change.

Important Questions on Thermodynamics

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Chemistry>Physical Chemistry>Thermodynamics>Terminology in 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>Terminology in Thermodynamics

When

5

moles of

He

gas expand isothermally and reversibly at

300 K

from

10

litres to

20

litres, the magnitude of the maximum work obtained in

J

is . [nearest integer ] (Given :

R = 8.3 J K^{- 1} {mol}^{- 1}

and

\log 2 = 0.3010

)

EASY

Chemistry>Physical Chemistry>Thermodynamics>Terminology in 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>Terminology in 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>Terminology in Thermodynamics

Write features of reversible process.

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Chemistry>Physical Chemistry>Thermodynamics>Terminology in Thermodynamics

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

$(A)$ Question Image

$(B)$

$(C)$

$(D)$

HARD

Chemistry>Physical Chemistry>Thermodynamics>Terminology in Thermodynamics

One mole of an ideal monoatomic gas undergoes two reversible processes $(A \to B$ and $B \to C)$ as shown in the given figure:

Question Image

$A \to B$ is an adiabatic process. If the total heat absorbed in the entire process $(A \to B$ and $B \to C)$ is ${RT}_{2} \ln 10$ , the value of $2 {logV}_{3}$ is
[Use molar heat capacity of the gas at constant pressure, $C_{p, m} = \frac{5}{2} R$ ]

EASY

Chemistry>Physical Chemistry>Thermodynamics>Terminology in 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

)

EASY

Chemistry>Physical Chemistry>Thermodynamics>Terminology in Thermodynamics

Define:
Reversible process

HARD

Chemistry>Physical Chemistry>Thermodynamics>Terminology in Thermodynamics

Three separate reversible processes

(1, 2 and 3)

are carried out with

1

mole of an ideal gas initially at STP. In these processes, the pressure (

P

) is measured while increasing any one of the quantities volume (

V

), temperature (

T

) and number of moles

(n)

, keeping the other two constant. Plots of

P (atm)

versus

X

are found to be linear, where

X = n

T (K)

1 / V ({lit}^{- 1})

. For the processes

1, 2

and

3

, the numerical values of the slopes

m_{1}, m_{2}

and

m_{3}

of the

P

versus

X

plots are found to follow the order

m_{1} > m_{2} > m_{3}

, respectively. The correct statement(s) about these processes is/are

HARD

Chemistry>Physical Chemistry>Thermodynamics>Terminology in 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>Terminology in Thermodynamics

During a reversible adiabatic process, the pressure of a gas is found to be proportional to the cube of its absolute temperature. The ratio

\frac{C_{p}}{C_{V}}

for the gas is

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Terminology in 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>Terminology in 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>Terminology in 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

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Chemistry>Physical Chemistry>Thermodynamics>Terminology in 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

]

EASY

Chemistry>Physical Chemistry>Thermodynamics>Terminology in 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>Terminology in Thermodynamics

Consider a cyclic process

P \to Q \to R \to P

for a system. Among the following, the combination of steps that can never lead to this cyclic process is

HARD

Chemistry>Physical Chemistry>Thermodynamics>Terminology in Thermodynamics

An ideal gas undergoes a reversible isothermal expansion from state

I

to state

II

followed by a reversible adiabatic expansion from state

II

to state

III .

The correct plot

(s)

representing the changes from state

I

to state

III

is(are)

( $p$ : pressure, $V$ : volume, $T$ : temperature, $H$ : enthalpy, $S$ : entropy)

EASY

Chemistry>Physical Chemistry>Thermodynamics>Terminology in Thermodynamics

In a closed insulated container, a liquid is stirred with a paddle to increase its temperature. In this process, which of the following is true?

Differentiate between the reversible and irreversible process on the basis of entropy change.

Important Questions on Thermodynamics

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