Chapter 16- chemical thermodynamics

The first law of thermodynamics can be given as __________.

Of the following, only __________ is not a state function.

When a system is at equilibrium, __________.

A reversible process is one that __________.

Which of the following statements is true?

For an isothermal process, ΔS = __________.

Which one of the following is always positive when a spontaneous process occurs?

The second law of thermodynamics states that __________.

Which of the following statements is false?

Which one of the following processes produces a decrease of the entropy of the system?

Consider a pure crystalline solid that is heated from absolute zero to a temperature above the boiling point of the liquid. Which of the following processes produces the greatest increase in the entropy of the substance?

Which one of the following correctly indicates the relationship between the entropy of a system and the number of different arrangements, W, in the system?

ΔS is positive for the reaction __________.

Which reaction produces an increase in the entropy of the system?

Of the following, the entropy of __________ is the largest.

Of the following, the entropy of gaseous __________ is the largest at 25°C and 1 atm.

For an isothermal process, the entropy change of the surroundings is given by the equation:

For the reaction
C2H6 (g) → C2H4 (g) + H2 (g)
ΔH° is + 137 kJ/mol and ΔS° is +120 J/K ∙ mol. This reaction is __________.

For the reaction
2C4H10 (g) + 13O2 (g) → 8CO2 (g) + 10H2O (g)
ΔH° is -125 kJ/mol and ΔS° is +253 J/K ∙ mol. This reaction is __________.

A reaction that is not spontaneous at low temperature can become spontaneous at high temperature if ΔH is __________ and ΔS is __________.

Consider the reaction:

NH3 (g) + HCl (g) → NH4Cl (s)
Given the following table of thermodynamic data,

determine the temperature (in °C) above which the reaction is nonspontaneous.

With thermodynamics, one cannot determine __________.

If ΔG° for a reaction is greater than zero, then __________.

The value of ΔG° at 25 °C for the oxidation of solid elemental sulfur to gaseous sulfur trioxide,

2S (s, rhombic) + 3O2 (g) → 2SO3 (g)

is __________ kJ/mol.

The value of ΔG° for a reaction conducted at 25°C is 3.05 kJ/mol. The equilibrium constant for a reaction is __________ at this temperature?

The normal boiling point of water is 100.0°C and its molar enthalpy of vaporization is 40.67 kJ/mol. What is the change in entropy in the system in J/K when 39.3 grams of steam at 1 atm condenses to a liquid at the normal boiling point?

The standard Gibbs free energy of formation of __________ is zero.

(a) H2O (l)
(b) O (g)
(c) I2 (s)

The standard Gibbs free energy of formation of __________ is zero.

(a) H2O (l)
(b) Mg (s)
(c) Br2 (l)

The standard Gibbs free energy of formation of __________ is zero.

(a) Si (s)
(b) F2 (g)
(c) Ni (s)

The value of ΔG° at 141.0°C for the formation of phosphorous trichloride from its constituent elements,

P2 (g) + 3Cl2 (g) → 2PCl3 (g)

is __________ kJ/mol. At 25.0°C for this reaction, ΔH° is -720.5 kJ/mol, ΔG° is -642.9 kJ/mol, and ΔS° is -263.7 J/K.

For the reaction
C(s) + H2O(g) → CO(g) + H2(g)

ΔH° = 131.3 kJ/mol and ΔS° = 127.6 J/K ∙ mol at 298 K. At temperatures greater than __________°C this reaction is spontaneous under standard conditions.

For a given reaction, ΔH = +35.5 kJ/mol and ΔS = +83.6 J/K-mol. The reaction is spontaneous __________. Assume that ΔH and ΔS do not vary with temperature.

In the Haber process, ammonia is synthesized from nitrogen and hydrogen:

N2 (g) + 3H2 (g) → 2NH3 (g)

ΔG° at 298 K for this reaction is -33.3 kJ/mol. The value of ΔG at 298 K for a reaction mixture that consists of 1.9 atm N2, 1.6 atm H2, and 0.65 atm NH3 is __________.

Phosphorous and chlorine gases combine to produce phosphorous trichloride:

P2 (g) + 3Cl2 (g) → 2PCl3 (g)

ΔG° at 298 K for this reaction is -642.9 kJ/mol. The value of ΔG at 298 K for a reaction mixture that consists of 1.5 atm P2, 1.6 atm Cl2, and 0.65 atm PCl3 is __________.

15) The equilibrium constant for a reaction is 0.35 at 25°C. What is the value of ΔG° (kJ/mol) at this temperature?

A reversible change produces the maximum amount of ________ that can be achieved by the system on the surroundings.

The melting of a substance at its melting point is an isothermal process.

The vaporization of a substance at its boiling point is an isothermal process

The entropy of a pure crystalline substance at 0°C is zero.

The more negative ΔG° is for a given reaction, the larger the value of the corresponding equilibrium constant, K.