Thermodynamics and Phases

This is an MCQ-based quiz for GRE on the topic of Thermodynamics and Phases.

This includes melting, freezing, vaporization, condensation, sublimation, and deposition.

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Which of the following reactions has a positive value for change in entropy (ΔS>0)?

3H2 +N2 ---> 2NH3 Water freezing into ice Water evaporates into water vapor A salt precipitates out of a saturated solution

Which is not characteristic of an endothermic reaction?

Releasing of energy to surroundings Breaking of a chemical bond Absorption of energy from surroundings The net change of enthalpy is positive A chemical reaction that feels cold

Which law of thermodynamics states that a crystal"s entropy at a temperature of absolute zero is equal to 0?

First law Zeroth law Third law Second law

Which of the following scenarios describes a reaction in equilibrium?

When ΔH is equal to TΔS When the forward rate is 0M/s When the enthalpy is equal to the entropy When Gibbs free energy is negative

Which of the following describes a transition from gas to solid?

Crystallization Vaporization Deposition Sublimation Fusion

If you create a perfect vacuum and place a glass of water into the vacuum at room temperature, what will happen to the water?

The water will freeze The water will boil The water will float about the vacuum Nothing will happen The water will boil very rapidly and then stop

Two moles of sodium chloride (NaCl) are added to 1kg of a mystery solvent. The addition of the NaCl caused an increase of 6K to the solvent"s boiling point.

Based on this information, what is the boiling constant for the solvent?

kb=1.5K/m

kb=3.0K/m

kb=1.0K/m

kb=6.0K/m

Which of the following options indicates that a chemical reaction is unfavorable?

ΔG is negative

All of these

ΔH is negative

ΔS is negative

Quiz/Test Summary

Title: Thermodynamics and Phases

Questions: 8