Question : 41.The reaction shown below at equilibrium. Use Le Chatelier’s principle : 1318412

41.The reaction shown below is at equilibrium. Use Le Chatelier’s principle to predict the effect of adding ammonia gas to the equilibrium reaction mixture.

N2(g) + 3H2(g) 2NH3(g)

A)The equilibrium position will remain unchanged.

B)The equilibrium position will shift to the right.

C)The equilibrium position will shift to the left.

D)The equilibrium constant will increase.

E)All of the nitrogen gas will be used up.

42.Thermodynamics is best described as which of the following?

A)the study of the rates at which reactions take place

B)the field of chemistry that determines the mechanisms of reactions

C)the study of Le Chatelier’s Principle

D)the study of energy, work, and heat

E)the study of the mass relationships in chemical reactions

43.A reaction will be spontaneous at all temperatures under which conditions?

A)The reaction is endothermic and accompanied by an increase of disorder.

B)The reaction is endothermic and accompanied by a decrease in disorder.

C)The reaction is exothermic and accompanied by an increase in disorder.

D)The reaction is exothermic and accompanied by a decrease in disorder.

E)The reaction has a positive value for free energy change.

44.Which of the following represents an exothermic reaction?

A)A(g) + B(g) ? 2C(g) ?H = +100 kcal

B)A(g) ? B(g) + 33 kcal

C)50 kcal + 2A(g) ? C(g) + D(s)

D)Both A and B are exothermic reactions.

E)Both A and C are exothermic reactions.

45.Which of the following is a process with a negative ?S?

A)H2O(l) ? H2(s)

B)CO2(s) ? CO2(g)

C)CaCO3(s) ? CaO(s) + CO2(g)

D)dissolving sugar in water

E)None of the choices are correct; ?S cannot be negative.

46.10.0 grams of octane are burned in a bomb calorimeter containing 2.00 ? 102 g H2O. If  the water temperature increases from 25.00oC to 37.00oC, how much energy was released by the system?

A)  7.40 kcal    B)  3.00 ? 103 kcal    C)  2.52 kcal    D)  1.65 kcal    E)  2.40 kcal

47.Which of the following will NOT increase the rate of a reaction?

A)increasing the size of the reaction vessel

B)adding a catalyst

C)increasing the temperature

D)increasing the concentration of the reactants

E)All of the above will increase the rate of a reaction.

48.For the reaction 2H2(g) + S2(g) 2H2S(g), determine the equilibrium constant at 700oC if at this temperature, the equilibrium concentrations are as follows:

[H2] = 0.208 M, [S2] = 1.13 ? 10-6 M, [H2S] = 0.725 M

A)  3.22 ? 106    B)  1.08 ? 107    C)  3.49    D)  4.55 ? 10-7    E)  441

49.Which of the following is a true statement concerning the specific heat of a substance?

A)Specific heat is the amount of heat required to raise one gram of a substance by one degree Celsius.

B)Specific heat is 1.00 cal for all substances.

C)Specific heat is the change in the temperature of a substance as it absorbs heat.

D)Specific heat is the amount of heat required to raise a mole of a substance by ten degrees.

E)Specific heat is the heat given off in a chemical reaction.

50.Which of the following pairs of substances has the substance with the highest entropy listed first?

A)Ni(s), Br2(l)D)Ne(g), H2O(l)

B)Hg(l), He(g)E)Both A and D are correct.

C)Br2(l), H2O(g)