Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 16

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IMPORTANT

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Standard enthalpy of vaporization $∆_{vap} H^{\circ}$ for water at $100 ° C$ is $40 \cdot 66 kJ {mol}^{- 1}$ . The internal energy change of vaporization of water at $100 ° C (in kJ {mol}^{- 1})$ is-

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Important Questions on Thermodynamics

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 17

The value of enthalpy change

(∆ H)

for the reaction

C_{2} H_{5} OH (l) + 3 O_{2} (g) \to 2 {CO}_{2} (g) + 3 H_{2} O (l) at 27 ° C is - 1366 \cdot 5 kJ {mol}^{- 1}

. The value of internal energy change for the above reaction at this temperature will be:

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Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 18

One mole of a non-ideal gas undergoes a change of state

(2 \cdot 0 atm, 3 \cdot 0 L, 95 K) \to (4 \cdot 0 atm, 5 \cdot 0 L, 245 K)

with a change in internal energy,

∆ U

= 30 \cdot 0 L atm

. The change in enthalpy

(∆ H)

of the process in

L atm

is

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IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 19

Two moles of an ideal gas expand isothermally and reversibly from

1 litre

to

10 litre

at

300 K

. The enthalpy change (in

kJ

) for the process is

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IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 20

The temperature of

2 moles

of an ideal gas is raised from

27 ° C

to

77 ° C

. What is the value for

∆ H - ∆ U

for the process? (

R = 8.3 J K^{- 1} {mol}^{- 1}

)

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IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 21

For the reaction

A \to B

,

∆ H = + 24 kJ / mole

. For the reaction

B \to C

,

∆ H = - 18 kJ / mole

. The decreasing order of enthalpy of A, B, C follows the order:

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 22

For the complete combustion of ethanol,

C_{2} H_{5} OH (l) + 3 O_{2} (g) \to 2 {CO}_{2} (g) + 3 H_{2} O (l)

, the amount of heat produced, as measured in bomb calorimeter, is

1364.47 kJ {mol}^{- 1} at 25 ° C

. Assuming ideality, the enthalpy of combustion,

∆_{c} H

, for the reaction will be

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

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IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 23

The combustion of benzene (l) gives

{CO}_{2} (g)

and

H_{2} O (l)

. Given that heat of combustion of benzene at constant volume is

- 3263.9 kJ {mol}^{- 1} at 25 ° C

, heat of combustion (

in kJ {mol}^{- 1}

) of benzene at constant pressure will be (

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

)

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11th CBSE

IMPORTANT

Pradeep's Chemistry Vol 1>Chapter 7 - Thermodynamics>Competition Focus>Q 24

Molar heat capacity of water in equilibrium with ice at constant pressure is