Question

Which of the processes below are spontaneous at room temperature? Select ALL that apply.

		The decomposition of liquid water into hydrogen and oxygen gasses.
		Sodium chloride salt dissolving in water.
		An ice cube melting in water at 25oC.
		An ice cube forming in water at 25oC.

Which of the following statements about entropy are true? Select ALL that apply.

		If the entropy of a system decreases, the entropy of the surroundings must increase.
		Gases generally have a higher entropy than liquids.
		Entropy increases as the disorder of the system increases.
		The entropy of a system is directly proportional to the number of ways the system can be put together.

Which of the following processes involve an increase of entropy? Select ALL that apply.

		The reaction: CaCO3(s)   → CaO(s) + CO2(g)
		The dissolution of CaCl2 in water.
		The freezing of water.
		The burning of gasoline.

Which of the following statements are true? Select ALL that apply.

		One way to state the Second Law of Thermodynamics is to say that for a spontaneous process ΔSuniverse > 0   .
		If the change in entropy for the system is +10.0 J/(mol K), then the change in entropy for the surroundings must be −10.0 J/(mol K).
		The entropy of a perfect crystal at 273 K and 1 atm of pressure is 0.
		For a reversible process at equilibrium ΔSuniverse = 0

The dissolution of NaCl in water (NaCl(s) → Na⁺(aq) + Cl^-(aq)) has a heat of reaction of 3.6 kJ/mol. What is the change in entropy for the surroundings when this reaction takes place (298K)? Answer in J/(mol K),

		−3.6
		3.6
		−12
		12

Answer 1