Spontaneous Reaction

Which of the following statements is/are true?

a) The rusting of iron by oxygen is a non-spontaneous reaction.

b) The addition of a catalyst to a reaction increases spontaneity.

c) The movement of heat from a cold object to a hot object is a non-spontaneous reaction.

d) The diffusion of perfume molecules from one side of a room to the other is a non-spontaneous reaction.

e) None of the above. 

(i) a ball rolling down a hill
(ii) a car rusting
(iii) the decomposition of water into H₂ gas and O₂ gas

2 NO (g) + O₂ (g) → 2 NO₂ (g)

An ideal gas is allowed to expand at constant temperature. What are the signs of ∆H, ∆S & ∆G.

Consider the freezing of liquid water at 30^°C. For this process what are the signs for ∆H, ∆S, and ∆G?

Predict the sign of ∆S in the system for each of the following processes:

a) Ag⁺ (aq) + Br ^- (aq) → AgBr (s)

b) CI₂ (g) → 2 CI ^- (g)

c) CaCO₃ (s) → CaO (s) + CO₂ (g)

d) Pb (s) at 50^°C → Pb (s) at 70^°C

For each of the following reactions state the signs of ∆H (enthalpy) and ∆S (entropy):

a) Fusion of ice.

b) Sublimation of CO₂

c) Vaporization of aqueous water.

d) Deposition of chlorine gas.

e) Condensation of water vapor. 

Diethyl ether (C₄H₁₀O₂, MW = 90.1 g/mol) has a boiling point of 35.6^oC and heat of vaporization of 26.7 kJ/mol. What is the change in entropy (in kJ/K) when 3.2 g of diethyl ether at 35.6^oC vaporizes at its boiling point?

2 NH₃ (g) + 2 O₂ (g) → NH₄NO₃ (s) + H₂O (l)

2 NO (g) + O₂ (g) → 2 NO₂ (g)