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

EASY

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A reversible process is the one carried out in infinitesimal steps while, an irreversible process is carried out in a finite number of steps.

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Important Questions on Thermodynamics

MEDIUM

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.

MEDIUM

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

MEDIUM

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?

A reversible process is the one carried out in infinitesimal steps while, an irreversible process is carried out in a finite number of steps.

Important Questions on Thermodynamics

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