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The enthalpy change of a reaction is independent of

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Important Questions on Thermodynamics

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Consider the following reaction:

CaO (s) + {CO}_{2} (g) ⟶ {CaCO}_{3} (s)

. The reaction is spontaneous at low temperature because

HARD

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

What will be the enthalpy of reaction

2 NO + O_{2} \to 2 {NO}_{2}

from the given formation enthalpy values ? The standard enthalpy of formation values for

O_{2},

NO

and

{NO}_{2}

are as follows:

O_{2} (g) : 0 kJ / mol, NO (g) : 90.25 kJ / mol

and

{NO}_{2} (g)

33.18 kJ / mol

respectively.

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

For the formation of

{NH}_{3} (g)

from its constituent elements at constant temperature and presssure, which of the following options is correct

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Which of the following relation is not correct?

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Two moles on an ideal gas is expanded isothermally and reversibly at 300 K form 1 L to 10 L. The enthalpy change in KJ is

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

$A$ fish swimming in water body when taken out from the water body is covered with a film of water of weight $36 g$ . When it is subjected to cooking at $100 ° C$ , then the internal energy for vaporization in ${kJmol}^{- 1}$ is integer]

[Assume steam to be an ideal gas. Given $Δ_{vap} H^{⊖}$ for water at $373 K$ and $1$ bar is $41.1 kJ {mol}^{- 1} : R = 8.31 J K^{- 1} {mol}^{- 1}$ ]

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Find the approximate value of

(ΔH - ΔU)

J \cdot {mol}^{- 1}

, for the formation of

CO

from its elements at

298 K

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

HARD

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

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:

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

For which of the following systems, the difference between $ΔH$ and $ΔU$ is not significant?

(i) Solids

(ii) Gases

(iii) Mixture of gases and liquids

(iv) Liquids

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

2

moles of a monoatomic ideal gas at

25^{o} C

is heated reversibly at a constant pressure of

2 atm

to reach a final temperature of

125^{o} C

. Calculate the

Δ H . (C_{v} = \frac{3}{2} R)

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

The internal energy change (in $J$ ) when $90 g$ of water undergoes complete evaporation at $100 ° C$ is ..............

(Given : ${ΔH}_{vap}$ for water at $373 K = 41 kJ / mol$ , $R = 8.314 {JK}^{- 1} {mol}^{- 1}$ )

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Which of the following process best describes atomization of

C H_{4} (g) ?

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Calculate the work done during the reactions represented by the following thermochemical equation at

300 K

\underset{(g)}{{CH}_{4}} + \underset{(g)}{2 O_{2}} \to \underset{(g)}{{CO}_{2}} + \underset{(l)}{2 H_{2} O}

(R = 8.314 {JK}^{- 1} {mol}^{- 1})

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

The standard enthalpy of vaporisation

Δ_{vap} H °

, for water at

100 ° C

40.66 kJ {mol}^{- 1}

. The internal energy of vaporisation of water at

100 ° C

(in

{kJmol}^{- 1}

) is (assume water vapour to behave like an ideal gas)

HARD

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Calculate the work done in the following reaction at $50 ° C$ . State whether work is done on the system or by the system.

${SO}_{2 (g)} + \frac{1}{2} O_{2 (g)} \to {SO}_{3 (g)}$

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

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

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

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

$(A)$ Question Image

$(B)$

$(C)$

$(D)$

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

A better criterion for ideality of a gas than

{(\frac{\partial U}{\partial V})}_{T} = 0

MEDIUM

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

Identify the equation in which change in enthalpy is equal to change in internal energy

EASY

Chemistry>Physical Chemistry>Thermodynamics>Enthalpy

During compression of a spring the work done is

10 k J

and

2 k J

escaped to the surroundings as heat. The change in internal energy,

Δ U (i n k J)

is:

The enthalpy change of a reaction is independent of

Important Questions on Thermodynamics

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