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If a rxn system has come to equilibrium, it can be made to run to completion

How do coefficients from a chem equilibrium appear when the chem equilibrium expression is written? a. as coefficients c. as subscripts b. as exponents d. They do not appear. If a rxn system has come to equilibrium, it can be made to run to completion a. only if it is not reversible.

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If a rxn system has come to equilibrium, it can be made to run to completion

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  1. How do coefficients from a chem equilibrium appear when the chem equilibrium expression is written? a. as coefficients c. as subscripts b. as exponents d. They do not appear. • If a rxn system has come to equilibrium, it can be made to run to completion a. only if it is not reversible. b. by applying Le Châtelier's principle. c. only if the temperature is low enough. d. under no circumstances. • The rate for a rxn between reactants L and M is proportional to the cube of [L] and the square of [M]. What is the rate law for this rxn? a. R = k[3L][2M] c. R = k[L]3[M]2 b. R = k[L][M] d. R = k[3L][2M][N]

  2. Which of the following substances has the lowest entropy? a. steam c. liquid water b. ice water d. crushed ice • An equilibrium mixture of SO2, O2, and SO3 gases at 1500 K is determined to consist of 0.344 M SO2, 0.172 M O2, and 0.56 M SO3. What is the equilibrium constant for the system at this temp? The balanced eqn for this rxn is 2SO2(g)+O2(g) 2SO3(g). a. 0.41 c. 6.7 b. 2.8 d. 15 • Which process is used to speed up chemical reactions? a. calorimetry c. activation b. catalysis d. inhibition

  3. The rate law for a reaction generally depends most directly on the a. net chemical reaction. b. rate-determining step. c. first step in the rxn pathway. d. last step in the rxn pathway. • At equilibrium, the total amount of the product(s) a. is always equal to the total amount of the reactants. b. is always greater than the total amount of the reactants. c. is always less than the total amount of the reactants. d. may be equal to, greater than, or less than the total amount of the reactants.

  4. Spontaneity is favored by large positive values of a. DG. c. DS. b. DH. d. absolute temperature. • A very high value of K indicates that a. equilibrium is reached slowly. b. reactants are favored. c. products are favored. d. equilibrium has been reached. • If the pressure on the equilibrium system N2(g) + O2(g)  2NO(g) decreases, a. the quantity of N2(g) decreases. b. the quantity of NO(g) increases. c. the quantity of NO(g) decreases. d. the quantities in the system do not change.

  5. A system that changes spontaneously without a favorable enthalpy change a. is impossible. b. becomes more disordered. c. becomes more ordered. d. releases heat. • What is the value of DG at 300 K for a reaction in which DH = –150 kJ/mol and DS = +2.00 kJ/mol·K? a. –750 kJ/mol c. +750 kJ/mol b. –450 kJ/mol d. +450 kJ/mol • Which of the following has the highest entropy when produced in a reaction? a. solid c. gas b. liquid d. aqueous solution

  6. If a reactant’s concentration is doubled and the reaction rate increases by a factor of 8, the exponent for that reactant in the rate law should be a. 0 d. 3 b. 1 e. ½ c. 2 • Which of the following is true in an endo rxn? a. energy of products < activation energy < energy of reactants b. energy of reactants < activation energy < energy of products c. energy of products < energy of reactants < activation energy d. energy of reactants < energy of products < activation energy

  7. In a spontaneous, exothermic dissolving process, which of these values has a negative sign? ΔG ΔH ΔT a. DG only b. DG and DH c. DH and DT d. DG, DH, and DT • All of the following apply to the reaction A(g) + B(g) <==> C(g) as it is carried out at constant temp in a rigid container EXCEPT: a. The total pressure decreases b. The rate of reaction decreases c. The entropy of the system decreases d. The number of molecules of C decreases e. The frequency of collisions between molecule A and B decreases

  8. 2O3(g) <==> 3O2(g) Keq = 2.5 x 1012 Consider a system at equilibrium based on the rxn above. In such a system, the concentration of O2(g) is a. constant & equal to the conc. of O3(g) b. constant & less than the conc. of O3(g) c. constant & greater than the conc. of O3(g) d. increasing & the conc. of O3(g) is increasing e. increasing & the conc. of O3(g) is decreasing

  9. 4NH3(g)+3O2(g) <==> 2N2(g)+6H2O(g)+energy Which of the following changes to the system at equilibrium shown above would cause the concentration of H2O to increase? a. The volume of the system was decreased at constant temperature b. The temperature of the system was increased at constant volume c. NH3 was removed from the system d. O2 was removed from the system e. N2 was removed from the system

  10. B • B • C • D • D • B • B • D • C • C • D • B • A • C • D • D • B • D • C • E Missed 0 to 5 = 5 pts Missed 6 to 12 = 3 pts Missed 13 to 20 = 1 pt

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