EASY

Earn 100

Assertion: Work done by a gas in reversible isothermal expansion is more than the work done by the gas in reversible adiabatic expansion if final volume is same.

Reason: Temperature remains constant in isothermal expansion, and not in adiabatic expansion.

50% studentsanswered this correctly

Important Questions on Chemical Thermodynamics

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First 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>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

The magnitude of work done by a gas that undergoes a reversible expansion along the path $A B C$ shown in the figure is _________.
Question Image

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

An ideal gas expands adiabatically against vacuum. Which of the following is correct for the given process?

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

A thermodynamic cycle in the pressure

(P)

-volume

(V)

plane is given below:
Question Image

AB

and

CD

are isothermal processes while

BC

and

DA

are adiabatic processes. The same cycle in the temperature

(T)

- entropy

(S)

plane is :

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First 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

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

An ideal gas initially at temperature, pressure and volume,

27 ° C, 1.00

bar and

10 L

respectively is heated at constant volume until pressure is

10.0

bar, it then undergoes a reversible isothermal expansion until pressure is

1.00 bar,

what is the total work

W

, during this process?

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

Under the isothermal condition, a gas at $300 K$ expands from $0.1 L$ to $0.25 L$ against a constant external pressure of $2$ bar. The work done by the gas is

(Given that $1 L$ bar $= 100 J$ )

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

For water at

100 ° C

and

1

bar,

Δ_{v a p} H - Δ_{v a p} U = \underline{} \times 10^{2} J {mol}^{- 1}

(Round off to the Nearest Integer)
[Use :

R = 8.31 J {mol}^{- 1} K^{- 1}]

[Assume volume of

H_{2} O (l)

is much smaller than volume of

H_{2} O (g)

. Assume

H_{2} O (g)

treated as an ideal gas]

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

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

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First 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

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

Five moles of an ideal gas at

293 K

is expanded isothermally from an initial pressure of

2.1 MPa

1.3 MPa

against at constant external pressure

4.3 MPa

. The heat transferred in this process is ___

{kJmol}^{- 1}

. (Rounded-off to the nearest integer)

[ Use $R = 8.314 J {mol}^{- 1} K^{- 1}$ ]

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

A cylinder containing an ideal gas (

0.1 m o l

1.0 d m^{3}

) is in thermal equilibrium with a large volume of

0.5

molal aqueous solution of ethylene glycol at its freezing point. If the stoppers

S_{1}

and

S_{2}

(as shown in the figure) are suddenly withdrawn, the volume of the gas in litres after equilibrium is achieved will be _____________.
(Given,

K_{f} (w a t e r) = 2.0 K k g m o l^{- 1}, R = 0.08 d m^{3} a t m K^{- 1} m o l^{- 1})

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

Three mole of an ideal gas expand isothermally and reversibly from

10 m^{3}

20 m^{3}

300 K,

calculate the work done?

(R = 8.314 J K^{- 1} {mol}^{- 1})

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

During the free expansion of an ideal gas in an isolated chamber,

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

At $25 ° C, 50 g$ of iron reacts with $HCl$ to form ${FeCl}_{2}$ . The evolved hydrogen gas expands against a constant pressure of $1 bar$ . The work done by the gas during this expansion is -_______ $J$ .

(Round off to the Nearest Integer)

[Given : $R = 8.314 J {mol}^{- 1} K^{- 1}$ . Assume, hydrogen is an ideal gas]

[Atomic mass off Fe is $55.85 u$ ]

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

When an ideal gas expands isothermally from

5 m^{3}

10 m^{3}

25 ° C

against a constant pressure of

10^{7} N \cdot m^{- 2}

, then the work done on the gas is

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

The magnitude of reversible work done by an ideal gas in four different processes: isothermal expansion, adiabatic expansion, constant pressure expansion, and free expansion are

W_{i}, W_{a}, W_{p}

, and

W_{f}

respectively. Choose the right order of sequence for the magnitude of the work done. (Change in the volume is same for all the processes.)

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of Thermodynamics

100 mole

H_{2} O_{2}

decompose at

1 bar

and

300 K

, the work is done (

kJ

) by one mole of

O_{2} (g)

as it expands against

1 bar

pressure is:

2 H_{2} O_{2} (l) ⇌ 2 H_{2} O (l) + O_{2} (g)

(R = 8 .3 J K^{- 1} {mol}^{- 1})

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Internal Energy and First Law of 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>Chemical Thermodynamics>Internal Energy and First 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:

Assertion: Work done by a gas in reversible isothermal expansion is more than the work done by the gas in reversible adiabatic expansion if final volume is same. Reason: Temperature remains constant in isothermal expansion, and not in adiabatic expansion.

Important Questions on Chemical Thermodynamics

Learn and Prepare for any exam you want !

Assertion: Work done by a gas in reversible isothermal expansion is more than the work done by the gas in reversible adiabatic expansion if final volume is same.

Reason: Temperature remains constant in isothermal expansion, and not in adiabatic expansion.