EASY

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All naturally occurring process are spontaneous processes.

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Important Questions on Chemical Thermodynamics

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

The heat of atomization of methane and ethane are

360 kJ {mol}^{- 1}

and

620 kJ {mol}^{- 1}

, respectively. The longest wavelength of light capable of breaking the

C - C

bond is (Avogadro's number

= 6.023 \times 10^{23}, h = 6.62 \times 10^{- 34} J s

)

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

The process with negative entropy change is:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

The heat of combustion of carbon to

C O_{2}

- 393.5 kJ / mol

. The heat released upon the formation of

35.2 g

C O_{2}

from carbon and oxygen gas is

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

Given:

C (graphite) + O_{2} (g) \to {CO}_{2} (g); Δ_{r} H^{o} = - 393 .5 kJ {mol}^{- 1}

H_{2} (g) + \frac{1}{2} O_{2} (g) \to H_{2} O (l); Δ_{r} H^{o} = - 285 .8 kJ {mol}^{- 1}

{CO}_{2} (g) + 2 H_{2} O (l) \to {CH}_{4} (g) + 2 O_{2} (g); Δ_{r} H^{o} = + 890 .3 kJ {mol}^{- 1}

Based on the above thermochemical equations, the value of

Δ_{r} H^{o}

298 K

for the reaction

C (graphite) + 2 H_{2} (g) \to {CH}_{4} (g)

will be:

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

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>Second Law of Thermodynamics

For which of the following processes,

∆ S

is negative?

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

Given:

(i)

C (graphite) + O_{2} (g) \to {CO}_{2} (g);

{ΔrH}^{Θ} = x kJ {mol}^{- 1}

(ii)

C (graphite) + \frac{1}{2} O_{2} (g) \to CO (g);

{ΔrH}^{Θ} = y kJ {mol}^{- 1}

(iii) CO (g) + \frac{1}{2} O_{2} (g) \to {CO}_{2} (g);

{ΔrH}^{Θ} = z kJ {mol}^{- 1}

Based on the above thermochemical equations, find out which one of the following algebraic relationships is correct?

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

Given

NO (g) + O_{3} (g) \to {NO}_{2} (g) + O_{2} (g) ∆ H = - 198 .9 kJ / mol

O_{3} (g) \to 3 / 2 O_{2} (g) ∆ H = - 142 .3 kJ / mol

O_{2} (g) \to 2 O (g) ∆ H = + 495 .0 kJ / mol

The enthalpy change

(∆ H)

for the following reaction is

N O (g) + O (g) \to N O_{2} (g)

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

The correct thermodynamic conditions for the spontaneous reaction at all temperatures is:

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

A process has

Δ H = 200 J m o l^{- 1}

and

Δ S = 40 J K^{- 1} m o l^{- 1} .

Out of the values given below choose the minimum temperature above which the process will be spontaneous:

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

Identify the INVALID equation.

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

For a spontaneous process,

MEDIUM

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

One mole of ethanol is produced reacting graphite,

H_{2}

and

O_{2}

together. The standard enthalpy of formation is

- 277.7 k J m o l^{- 1} .

Calculate the standard enthalpy of the reaction when

4

moles of graphite is involved

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

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

p_{i}

p_{f}

, the entropy change is given by

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

The standard enthalpies of formation of ${CO}_{2} (g)$ $, H_{2} O (l)$ and glucose (s) at $2 5^{o} C$ are $- 400 kJ / mol$ , $- 300 kJ / mol$ and $- 1300 kJ / mol$ , respectively. The standard enthalpy combustion per gram of glucose at $2 5^{o} C$ is

( ${ΔH}_{f}^{0} = - 1300 kJ {mol}^{- 1}$ for Glucose)

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

For a reaction,

A (g) \to A (l); ΔH = - 3 RT .

The correct statement for the reaction is

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

The enthalpy change on freezing of

1 mol

of water at

5 ° C

to ice at

- 5 ° C

is:

(Given

Δ_{fus} H = 6 kJ {mol}^{- 1}

0 ° C,

C_{p} (H_{2} O, l) = 75 .3 J {mol}^{- 1} K^{- 1}

C_{p} (H_{2} O, s) = 36 .8 J {mol}^{- 1} K^{- 1}

)

HARD

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

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

)

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

At what temperature, a chemical reaction will have following values?

$ΔG = 4 kJ, ΔH = - 60 kJ, ΔS = - 160 J$

EASY

Chemistry>Physical Chemistry>Chemical Thermodynamics>Second Law of Thermodynamics

For spontaneous polymerisation, which of the following is (are) correct?

All naturally occurring process are spontaneous processes.

Important Questions on Chemical Thermodynamics

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