369543
Calculate the change of entropy for the process, water (liquid) to water (vapour) involving \({\rm{\Delta }}{{\rm{H}}_{{\rm{vap }}}} = 40850\;{\rm{J}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}\) at 373 K .
369544
Assertion : Heat of sublimation is the sum of heat of fusion and heat of vaporisation. Reason : Heat of the reaction or enthalpy change is same whether reaction takes place in one step or in a number of steps.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Sublimation involves the transition from solid to vapor with enthalpy change of \(\Delta \mathrm{H}_{\text {Sub }}\). Similarly, the transition from solid to liquid has an enthalpy change of \(\Delta \mathrm{H}_{\text {Fus }}\) and from liquid to gas it is \(\Delta \mathrm{H}_{\text {vap }}\). Therefore, the overall enthalpy change \((\Delta \mathrm{H})\) can be calculated as the sum of these changes: \(\Delta \mathrm{H}_{\text {Sub }}=\Delta \mathrm{H}_{\text {Fus }}+\Delta \mathrm{H}_{\text {Vap }}\). So, option (1) is correct.
CHXI06:THERMODYNAMICS
369545
Enthalpy of sublimation of a substance is equal to
1 enthalpy of fusion + enthalpy of vapourisation
2 enthalpy of fusion
3 enthalpy of vapourisation
4 twice the enthalpy of vapourisation
Explanation:
Enthalpy of sublimation of a substance is equal to enthalpy of fusion + enthalpy of vapourisation. Sublimation is direct conversion of solid to vapour, i.e., solid \(\mathrm{\rightarrow}\) Vapour Writing in two steps, we have solid \(\mathrm{\rightarrow}\) liquid \(\mathrm{\rightarrow}\) Vapour Solid \(\mathrm{\rightarrow}\) liquid requires enthalpy of fusion Liquid \(\mathrm{\rightarrow}\) vapour requires enthalpy of vapourisation.
NCERT Exemplar
CHXI06:THERMODYNAMICS
369546
One mole of acetone requires less heat to vapourise than \(\mathrm{1 \mathrm{~mol}}\) of water. The liquid that has higher enthalpy of vapourisation is
1 Water
2 Acetone
3 Both have same enthalpy of vapourisation
4 Data insufficient
Explanation:
Lower is the vapour pressure higher is the amount of the heat required for vapourisation process.
NEET Test Series from KOTA - 10 Papers In MS WORD
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CHXI06:THERMODYNAMICS
369543
Calculate the change of entropy for the process, water (liquid) to water (vapour) involving \({\rm{\Delta }}{{\rm{H}}_{{\rm{vap }}}} = 40850\;{\rm{J}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}\) at 373 K .
369544
Assertion : Heat of sublimation is the sum of heat of fusion and heat of vaporisation. Reason : Heat of the reaction or enthalpy change is same whether reaction takes place in one step or in a number of steps.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Sublimation involves the transition from solid to vapor with enthalpy change of \(\Delta \mathrm{H}_{\text {Sub }}\). Similarly, the transition from solid to liquid has an enthalpy change of \(\Delta \mathrm{H}_{\text {Fus }}\) and from liquid to gas it is \(\Delta \mathrm{H}_{\text {vap }}\). Therefore, the overall enthalpy change \((\Delta \mathrm{H})\) can be calculated as the sum of these changes: \(\Delta \mathrm{H}_{\text {Sub }}=\Delta \mathrm{H}_{\text {Fus }}+\Delta \mathrm{H}_{\text {Vap }}\). So, option (1) is correct.
CHXI06:THERMODYNAMICS
369545
Enthalpy of sublimation of a substance is equal to
1 enthalpy of fusion + enthalpy of vapourisation
2 enthalpy of fusion
3 enthalpy of vapourisation
4 twice the enthalpy of vapourisation
Explanation:
Enthalpy of sublimation of a substance is equal to enthalpy of fusion + enthalpy of vapourisation. Sublimation is direct conversion of solid to vapour, i.e., solid \(\mathrm{\rightarrow}\) Vapour Writing in two steps, we have solid \(\mathrm{\rightarrow}\) liquid \(\mathrm{\rightarrow}\) Vapour Solid \(\mathrm{\rightarrow}\) liquid requires enthalpy of fusion Liquid \(\mathrm{\rightarrow}\) vapour requires enthalpy of vapourisation.
NCERT Exemplar
CHXI06:THERMODYNAMICS
369546
One mole of acetone requires less heat to vapourise than \(\mathrm{1 \mathrm{~mol}}\) of water. The liquid that has higher enthalpy of vapourisation is
1 Water
2 Acetone
3 Both have same enthalpy of vapourisation
4 Data insufficient
Explanation:
Lower is the vapour pressure higher is the amount of the heat required for vapourisation process.
369543
Calculate the change of entropy for the process, water (liquid) to water (vapour) involving \({\rm{\Delta }}{{\rm{H}}_{{\rm{vap }}}} = 40850\;{\rm{J}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}\) at 373 K .
369544
Assertion : Heat of sublimation is the sum of heat of fusion and heat of vaporisation. Reason : Heat of the reaction or enthalpy change is same whether reaction takes place in one step or in a number of steps.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Sublimation involves the transition from solid to vapor with enthalpy change of \(\Delta \mathrm{H}_{\text {Sub }}\). Similarly, the transition from solid to liquid has an enthalpy change of \(\Delta \mathrm{H}_{\text {Fus }}\) and from liquid to gas it is \(\Delta \mathrm{H}_{\text {vap }}\). Therefore, the overall enthalpy change \((\Delta \mathrm{H})\) can be calculated as the sum of these changes: \(\Delta \mathrm{H}_{\text {Sub }}=\Delta \mathrm{H}_{\text {Fus }}+\Delta \mathrm{H}_{\text {Vap }}\). So, option (1) is correct.
CHXI06:THERMODYNAMICS
369545
Enthalpy of sublimation of a substance is equal to
1 enthalpy of fusion + enthalpy of vapourisation
2 enthalpy of fusion
3 enthalpy of vapourisation
4 twice the enthalpy of vapourisation
Explanation:
Enthalpy of sublimation of a substance is equal to enthalpy of fusion + enthalpy of vapourisation. Sublimation is direct conversion of solid to vapour, i.e., solid \(\mathrm{\rightarrow}\) Vapour Writing in two steps, we have solid \(\mathrm{\rightarrow}\) liquid \(\mathrm{\rightarrow}\) Vapour Solid \(\mathrm{\rightarrow}\) liquid requires enthalpy of fusion Liquid \(\mathrm{\rightarrow}\) vapour requires enthalpy of vapourisation.
NCERT Exemplar
CHXI06:THERMODYNAMICS
369546
One mole of acetone requires less heat to vapourise than \(\mathrm{1 \mathrm{~mol}}\) of water. The liquid that has higher enthalpy of vapourisation is
1 Water
2 Acetone
3 Both have same enthalpy of vapourisation
4 Data insufficient
Explanation:
Lower is the vapour pressure higher is the amount of the heat required for vapourisation process.
369543
Calculate the change of entropy for the process, water (liquid) to water (vapour) involving \({\rm{\Delta }}{{\rm{H}}_{{\rm{vap }}}} = 40850\;{\rm{J}}\;{\rm{mo}}{{\rm{l}}^{ - 1}}\) at 373 K .
369544
Assertion : Heat of sublimation is the sum of heat of fusion and heat of vaporisation. Reason : Heat of the reaction or enthalpy change is same whether reaction takes place in one step or in a number of steps.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Sublimation involves the transition from solid to vapor with enthalpy change of \(\Delta \mathrm{H}_{\text {Sub }}\). Similarly, the transition from solid to liquid has an enthalpy change of \(\Delta \mathrm{H}_{\text {Fus }}\) and from liquid to gas it is \(\Delta \mathrm{H}_{\text {vap }}\). Therefore, the overall enthalpy change \((\Delta \mathrm{H})\) can be calculated as the sum of these changes: \(\Delta \mathrm{H}_{\text {Sub }}=\Delta \mathrm{H}_{\text {Fus }}+\Delta \mathrm{H}_{\text {Vap }}\). So, option (1) is correct.
CHXI06:THERMODYNAMICS
369545
Enthalpy of sublimation of a substance is equal to
1 enthalpy of fusion + enthalpy of vapourisation
2 enthalpy of fusion
3 enthalpy of vapourisation
4 twice the enthalpy of vapourisation
Explanation:
Enthalpy of sublimation of a substance is equal to enthalpy of fusion + enthalpy of vapourisation. Sublimation is direct conversion of solid to vapour, i.e., solid \(\mathrm{\rightarrow}\) Vapour Writing in two steps, we have solid \(\mathrm{\rightarrow}\) liquid \(\mathrm{\rightarrow}\) Vapour Solid \(\mathrm{\rightarrow}\) liquid requires enthalpy of fusion Liquid \(\mathrm{\rightarrow}\) vapour requires enthalpy of vapourisation.
NCERT Exemplar
CHXI06:THERMODYNAMICS
369546
One mole of acetone requires less heat to vapourise than \(\mathrm{1 \mathrm{~mol}}\) of water. The liquid that has higher enthalpy of vapourisation is
1 Water
2 Acetone
3 Both have same enthalpy of vapourisation
4 Data insufficient
Explanation:
Lower is the vapour pressure higher is the amount of the heat required for vapourisation process.