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Model Paper 5 — Chemistry STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 ScienceChemistryModel Paper 53 Marks
Question
1. Two ideal gases under the same pressure and temperature are allowed to mix in an isolated system.
What will be the sign of entropy change?
2. Water can be lifted into the water tank at the top of the house with the help of a pump. Then why is it not considered to be spontaneous?
3. What is the enthalpy change for an adiabatic process?
✓

Answer

1. When two ideal gases at the same pressure and temperature are allowed to mix in an isolated system, the entropy change is positive because degrees of freedom increases on mixing the gases.
2. A spontaneous process should occur continuously by itself after initiation. But this is not so in the given case because water will go up so long as the pump is working.
So, this process is not considered as a spontaneous process.
3. For an adiabatic process,
$
\Delta H=0
$

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