Entropy, Spontaneity and Second Law of Thermodynamics Quiz

Which of the following processes demonstrates an increase in entropy?

• The crystallization of salt from a saturated solution.

• The compression of a gas at constant temperature.

• The sublimation of dry ice (solid CO₂) to gaseous CO₂.

• The formation of ice crystals from liquid water at -10°C.

Which process is likely to be spontaneous based on entropy alone?

• The formation of a protein from its amino acid constituents.

• The mixing of two different gases in a container.

• The cooling of a hot metal block.

• The condensation of steam into liquid water.

Which of the following processes leads to a decrease in entropy?

• Melting of ice.

• Evaporation of a liquid.

• Dissolving salt in water.

• The formation of a precipitate from a solution.

Which scenario represents the greatest increase in entropy?

• A liquid freezing.

• A solid melting.

• A gas condensing.

• A liquid evaporating.

Which of the following is most likely to be a spontaneous process based on entropy?

• Organizing a messy room.

• Iron rusting.

• Water freezing at 25°C.

• Separating a mixture of gases into its pure components.

Which process results in a decrease in the number of microstates and therefore a decrease in entropy?

• The expansion of a balloon.

• The dissolving of sugar in tea.

• The compression of a gas.

• The heating of a solid.

Consider a chemical reaction where gases are formed from solids and liquids. Which of the following is true regarding the entropy change (ΔS)?

• ΔS is negative.

• ΔS is zero.

• ΔS is positive.

• ΔS cannot be determined.

Which of the following reactions would have the largest positive ΔS?

• N2(g)+3H2(g)→2NH3(g)

• 2H2O(l)→2H2(g)+O2(g)

• Ag+(aq)+Cl−(aq)→AgCl(s)

• C(s)+O2(g)→CO2(g)

1. The second law of thermodynamics introduces the concept of:

• Energy conservation

• Entropy

• Enthalpy

•  Internal energy

Which of the following processes is considered irreversible according to the second law of thermodynamics?

• A perfectly elastic collision

• The melting of ice at its melting point in a controlled environment.

• The free expansion of a gas into a vacuum.

• A frictionless pendulum swinging.