Thermodynamic Laws Quiz

What is a spontaneous change?

• A change that requires external influence

• A change that happens without outside influences

• A change that is always exothermic

• A change that occurs only at high temperatures

According to the second law of thermodynamics, what does the universe tend towards?

• A state of greater order

• A state of lower energy

• A state of equilibrium

• A state of greater disorder

Which of the following is an example of an irreversible process?

• Melting of ice

• Rusting of iron

• Freezing of water

• Dissolving sugar in water

What must be true for a spontaneous process to occur according to the second law of thermodynamics?

• The entropy of the universe must decrease

• The free energy change must be positive

• The system must be at equilibrium

• The free energy change must be negative

Which of the following statements about entropy is true?

• Entropy is constant in all processes

• Entropy increases when gases are formed from solids

• Entropy is a measure of order

• Entropy decreases in exothermic reactions

What does the third law of thermodynamics state?

• Entropy of a perfect crystal at absolute zero is zero

• It is impossible to reach absolute zero

• Entropy can be negative

• All substances have the same entropy

In the context of spontaneity, what does a negative ΔG indicate?

• The reaction is nonspontaneous

• The reaction is spontaneous

• The system is at equilibrium

• The reaction is endothermic

Which of the following processes is spontaneous at room temperature?

• Freezing of water

• Condensation of steam

• Rusting of iron

• Melting of ice

What is the relationship between ΔH, ΔS, and ΔG?

• ΔG = ΔH - TΔS

• ΔG = TΔS - ΔH

• ΔG = ΔH + ΔS

• ΔG = ΔH + TΔS

How does temperature affect the spontaneity of a reaction?

• It only affects exothermic reactions

• It has no effect

• It always makes reactions spontaneous

• It can change the sign of ΔG