Exam 17: Thermodynamics: Entropy, free Energy, and Equilibrium

The reaction 2 H₂(g)+ O₂(g)→ 2 H₂O(g)is spontaneous at 25°C.The addition of a catalyst will ________ (decrease,increase,not change)the rate of reaction and ________ (decrease,increase,not change)the spontaneity of the reaction.

Which of the following processes are spontaneous? I.dissolving more solute in an unsaturated solution II.dissolving more solute in a saturated solution III.dissolving more solute in a supersaturated solution

A reaction has ΔG° = + 21.5 kJ/mol,ΔH° = + 25.0 kJ/mol,and ΔS° = + 15.0 J/mol∙K can become spontaneous at a temperature of ________ K.

Entropy is a measure of

Which equation can be used to determine ΔG_form for C₂H₅OH from its elemental parts.Be sure that the reaction is balanced.

For any thermodynamic function Y,ΔY° for a reaction refers to the change in Y for the process in which

For the reaction N₂(g)+ O₂(g)→ 2NO(g),ΔH° = 180.4 kJ/mol and ΔS° = 24.9 J/K.Is there a temperature at which the spontaneity of this reaction be changed,either from spontaneous to nonspontaneous or nonspontaneous to spontaneous? If so,estimate the temperature.

The standard free energy for a reaction is ΔG° = -33.0 kJ.At 25°C the equilibrium constant for this reaction,K_p = ________.

Which of the following statements must be true for the entropy of a pure solid to be zero? I.The temperature must be 0 K. II.The solid must be crystalline,not amorphous. III.The solid must be perfectly ordered. IV.The solid must be an element.

For the reaction 3 C₂H₂(g)→ C₆H₆(l)at 25°C,the standard enthalpy change is -631 kJ and the standard entropy change is -430 J/K.Calculate the standard free energy change at 25°C?

Which of the following is a criterion for spontaneity that holds for any process?

In figure (1)below oxygen molecules,represented by unshaded spheres,and chlorine molecules,represented by shaded spheres,are in separate compartments.Figure (2)shows the equilibrium state of the system after the stopcock separating the two compartments is opened.Assuming the oxygen and the chlorine behave as ideal gases,what are the signs (+,-,or 0)of ΔH,ΔS,and ΔG for this process?

For the reaction below ΔG° = +33.0 kJ,ΔH° = +92.2 kJ,and ΔS° = +198.7 J/K.Estimate the temperature at which this reaction becomes spontaneous. 2 NH₃(g)→ N₂(g)+ 3 H₂(g)

Which of the following are unstable with respect to their constituent elements at 25°C?

At 25°C,ΔH° = 1.895 kJ and ΔS° = -3.363 J/K for the transition C(graphite)→ C(diamond) Based on these data,

-The figure above represents the nonspontaneous reaction O₂(g)→ 2O(g).What are the signs (+ or -)of ΔH,ΔS,and ΔG for this process?

Standard molar entropies,S°,in J/Kmol,are given below each reactant and product in the reaction shown below.The standard entropy of reaction,ΔS°,for this reaction is ________ J/K. S(s,rhombic)+ O₂(g)→ SO₂(g) 31.8 205.0 248.1

The Boltzmann formula is S = k ln W.A perfect crystal has a molar entropy of 0 at absolute zero because

For the evaporation of water during perspiration on a hot,dry day,

-According to the diagram above,