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1. For the dissociation reaction of the acid HF: HF<-->H++ F -
DS is observed to be negative. The BEST explanation for this is:

This is the expected result since each HF molecule produces two ions when it dissassociates
Hydration of the ions produces the negative value of DS.
The reation is expected to be exothermic and thus D should be negative.
The reaction is expected to be endothermic and thus D should be negative.
None of these can explain the negative value of DS.

2. The 3rd Law of Thermodynamics States that:
Energy is artificial
Energy can neither be created nor lost
The entropy of the universe is decreasing
The entropy is zero at zero K for a perfect crystal
none of the above

3. Choose the correct statement.
Exothermic reactions are always spontaneous
High temperature ensures a spontaneous reaction
Free energy is independent of temperature
A reaction with negative DS cannot be spontaneous
none of the above

4. Which of the following statements is always TRUE for a spontaneous process?

I. DSsys > 0
II. DSsurr > 0
III. DSuniv > 0
IV. GSsys > 0


I
III
IV
I and III
III and IV

5. For the gas sample B, this reaction is endothermic: B-->2B. The reaction is:
always spontaneous
only at high temperatures
only at low temperatures
never spontaneous
none of the above

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