For the process H 2 O l → H 2 O g at T = 100 o C and 1 atmosphere pressure, the correct choice is-

∆ S s y s t e m > 0 a n d ∆ S s u r r o u n d i n g < 0

∆ S s y s t e m > 0 a n d ∆ S s u r r o u n d i n g > 0

∆ S s y s t e m < 0 a n d ∆ S s u r r o u n d i n g > 0

∆ S s y s t e m < 0 ∆ S s u r r o u n d i n g < 0

EASY

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During which phenomenon does entropy decrease?

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Important Questions on Chemical Thermodynamics

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

The true statement amongst the following is:

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

The entropy change in the isothermal reversible expansion of 2 moles of an ideal gas from 10 to 100 at 300 K is

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

For the process

H_{2} O (l) \to H_{2} O (g)

T = 100^{o} C

and

1

atmosphere pressure, the correct choice is-

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

Which of the following show an increase in entropy?

I. Boiling of water

II. Melting of ice

III. Freezing of water

IV. Formation of hydrogen gas from water

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

One mole of an ideal gas at

300 K

in thermal contact with its surroundings expands isothermally from

1.0 L

2.0 L

against a constant pressure of

3.0 atm

. In this process, the change in entropy of the surroundings

(∆ S_{s u r r})

J K^{- 1}

is:

(1 L atm = 101.3 J)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

Calculate the entropy change in melting

1

mole of ice at

273 K ({ΔH}_{f}^{°} = 6.025 kJ {mol}^{- 1})

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

The latent heat of melting of ice at

0 ° C is 6 kJ {mol}^{- 1}

. The entropy change during the melting in

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

is closets to-

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

A container is divided into two compartments by a removable partition as shown below:

Question Image

In the first compartment, $n_{1}$ moles of ideal gas He is present in a volume $V_{1} .$ In the second compartment, $n_{2}$ moles of ideal gas $Ne$ is present in a volume $V_{2} .$ The temperature and pressure in both the compartments are $T$ and $P,$ respectively. Assuming $R$ is the gas constant, the total change in entropy upon removing the partition when the gases mix irreversibly is:

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

The entropy change associated with the conversion of

1 k g

of ice at

273 K

to water vapours at

383 K

is:

(Specific heat of water liquid and water vapour are

4.2 k J K^{-}

and

2.0 k J K^{- 1} k g^{- 1}

; heat of liquid fusion and vaporization of water are

334 k J k g^{- 1}

and

2491 k J k g^{- 1}

, respectively). (

l o g

273 = 2.436, \log 373 = 2.572, \log 383 = 2.583

)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

The process with negative entropy change is:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

For a sample of perfect gas, when its pressure is changed isothermally from

p_{i}

p_{f}

, the entropy change is given by

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

For the process

H_{2} O (l) \overset{1 bar, 373 K}{⇌} H_{2} O (g)

, the correct set of thermodynamic parameters is

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

When the same quantity of heat is absorbed by a system at two different temperatures

T_{1}

and

T_{2}

, such that

T_{1} > T_{2}

, change in entropies are

Δ S_{1}

and

Δ S_{2}

respectively. Then:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

For the reaction,

2 Cl (g) \to {Cl}_{2} (g)

, the correct option is

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

For the following reaction

${Fe}_{2} O_{3 (s)} + 3 {CO}_{(g)} ⟶ 2 {Fe}_{(s)} + 3 {CO}_{2 (g)} ΔH ° = - 29.8 kJ$ and $ΔS ° = 15 {JK}^{- 1}$ . What is the value of ${ΔS}_{(total)}$ at $298 K$ ?

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

During which of the following processes, does entropy decrease ?

(A) Freezing of water to ice at $0 ° C$
(B) Freezing of water to ice at $- 10 ° C$
(C) $N_{2} (g) + 3 H_{2} (g) \to 2 {NH}_{3} (g)$
(D) Adsorption of $CO (g)$ and lead surface
(E) Dissolution of $NaCl$ in water

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

Standard molar entropy is

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

For which of the following processes,

∆ S

is negative?

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

Standard entropies of

X_{2}, Y_{2}

and

{XY}_{3}

are

60, 30

and

50

{JK}^{- 1} {mol}^{- 1}

respectively. For the reaction

\frac{1}{2} X_{2} + \frac{3}{2} Y_{2} ⇌ {XY}_{3},

ΔH = - 30 kJ

to be at equilibrium, the temperature should be:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Spontaneous processes (Irreversible process)

In which case change in entropy is negative?

During which phenomenon does entropy decrease?

Important Questions on Chemical Thermodynamics

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