Entropy of Ph...

Entropy of Phase Change

Trending Questions

When water is cooled to ice, its entropy

increases
decreases
remains the same
becomes zero

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When water is cooled to ice, its entropy

increases
decreases
remains the same
becomes zero

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Q. Calculate the change in entropy for fusion of 1 mole of ice. The melting point of ice is 273 K and molar enthalpy of fusion for ice = 6.0 kJ

m o l e^{- 1}

$△ S_{f}$ =21.97 $J K^{- 1} m o l^{- 1}$
$△ S_{f}$ =21.87 $J K^{- 1} m o l^{- 1}$
$△ S_{f}$ =21.78 $J K^{- 1} m o l^{- 1}$
$△ S_{f}$ =21.79 $J K^{- 1} m o l^{- 1}$

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Q. Predict in how many of the following processes entropy change of the system is positive .
(i)

C a C O_{3} (s) \to C a O (s) + C O_{2} (g)

(ii)

N_{2} (g) + 3 H_{2} (g) \to 2 N H_{3} (g)

(iii)

H C l (g) + N H_{3} (g) \to N H_{4} C l (s)

(iv)

2 S O_{2} (g) + O_{2} (g) \to 2 S O_{3} (g)

(v) Cooling of

N_{2} (g)

from

20^{o} C t o - 50^{o} C

In all the processess
3
1
2

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Q. At 373 K, steam and water are in equilibrium and

△_{v a p} H = 40.98 k J m o l^{- 1} .

What will be entropy change for conversion of water into steam?

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

$109.8 J K^{- 1} m o l^{- 1}$
$31 J K^{- 1} m o l^{- 1}$
$21.98 J K^{- 1} m o l^{- 1}$
$326 J K^{- 1} m o l^{- 1}$

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Calculate entropy change for vaporization of 1 mole of liquid water to steam at $100^{\circ} C$ if $Δ H_{v}$ =40.8 kJ $m o l^{- 1}$ .

$Δ S_{v} = 107.38 J K^{- 1} m o l^{- 1}$
$Δ S_{v} = 109.48 J K^{- 1} m o l^{- 1}$
$Δ S_{v} = 109.38 J K^{- 1} m o l^{- 1}$
$Δ S_{v} = 107.38 J K^{- 1} m o l^{- 1}$

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Q. At 373 K, steam and water are in equilibrium and

△_{v a p} H = 40.98 k J m o l^{- 1} .

What will be entropy change for conversion of water into steam?

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

$109.8 J K^{- 1} m o l^{- 1}$
$31 J K^{- 1} m o l^{- 1}$
$21.98 J K^{- 1} m o l^{- 1}$
$326 J K^{- 1} m o l^{- 1}$

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Q. The enthalpy of vaporization of water at

100^{o} C

40.63 k J m o l^{- 1}

. It's entropy change for the vaporization would be :

$406.3 J K^{- 1} m o l^{- 1}$
$108.9 J K^{- 1} m o l^{- 1}$
$108.9 k J K^{- 1} m o l^{- 1}$
$4063 k J K^{- 1} m o l^{- 1}$

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Q. Predict in how many of the following processes entropy change of the system is positive .
(i)

C a C O_{3} (s) \to C a O (s) + C O_{2} (g)

(ii)

N_{2} (g) + 3 H_{2} (g) \to 2 N H_{3} (g)

(iii)

H C l (g) + N H_{3} (g) \to N H_{4} C l (s)

(iv)

2 S O_{2} (g) + O_{2} (g) \to 2 S O_{3} (g)

(v) Cooling of

N_{2} (g)

from

20^{o} C t o - 50^{o} C

In all the processess
3
1
2

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Q. The enthalpy of vaporisation of liquid diethyl ether

(C_{2} H_{5})_{2} O

26 {kJ mol}^{- 1}

at its boiling point

35^{o} C .

Calculate

△ S^{o}

for conversion of vapour to liquid (condensation) at

35^{o} C .

$- 84.41 {J K}^{- 1} {mol}^{- 1}$
$+ 84.41 {J K}^{- 1} {mol}^{- 1}$
$- 48.41 {J K}^{- 1} {mol}^{- 1}$
$+ 48.41 {J K}^{- 1} {mol}^{- 1}$

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Q. The enthalpy of vaporization of water at

100^{o} C

40.63 k J m o l^{- 1}

. It's entropy change for the vaporization would be :

$406.3 J K^{- 1} m o l^{- 1}$
$108.9 J K^{- 1} m o l^{- 1}$
$108.9 k J K^{- 1} m o l^{- 1}$
$4063 k J K^{- 1} m o l^{- 1}$

View Solution