JEE MAIN - Chemistry (2019 - 9th January Evening Slot - No. 23)
The entropy change associated with the conversion of 1 kg of ice at 273 K to water vapours at 383 K is :
(Specific heat of water liquid and water vapour are 4.2 kJ K$$-$$1 kg$$-$$1 and 2.0 kJ K$$-$$1 kg$$-$$1; heat of liquid fusion and vapourisation of water are 334 kJ$$-$$1 and 2491 kJ kg$$-$$1, respectively). (log 273 = 2.436, log 373 = 2.572, log 383 = 2.583)
(Specific heat of water liquid and water vapour are 4.2 kJ K$$-$$1 kg$$-$$1 and 2.0 kJ K$$-$$1 kg$$-$$1; heat of liquid fusion and vapourisation of water are 334 kJ$$-$$1 and 2491 kJ kg$$-$$1, respectively). (log 273 = 2.436, log 373 = 2.572, log 383 = 2.583)
7.90 kJ kg$$-$$1 K$$-$$1
2.64 kJ kg$$-$$1 K$$-$$1
8.49 kJ kg$$-$$1 K$$-$$1
9.26 kJ kg$$-$$1 K$$-$$1
Explanation
_9th_January_Evening_Slot_en_23_1.png)
$$\Delta {S_1} = {{\Delta {H_{fusion}}} \over {273}} = {{334} \over {273}} = 1.22$$
$$\Delta {S_2} = 4.2\ell N\left( {{{363} \over {273}}} \right) = 1.31$$
$$\Delta {S_3} = {{\Delta {H_{vap}}} \over {373}} = {{2491} \over {373}} = 6.67$$
$$\Delta {S_4} = 2.0\ell n\left( {{{383} \over {373}}} \right) = 0.05$$
$$\Delta {S_{total}} = 9.26\,$$ kJ Kg$$-$$1 K$$-$$1
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