Chap 14 Equilibrium quizzes

For which of the following equilibrium systems will the amounts of reactants increase with an increase in the container volume? (1) C(g) + CO2(g)<=> 2CO(g) (2) N2(g) + 3H2(g) <=> 2NH3(g) (3) 2NO(g) + O2(g) <=> 2NO2(g) (1) only (2) only (1) and (3) only (2) and (3) only

(2) and (3) only

Consider the following equilibrium system: CO(g) + H2O(g) <=> CO2(g) + H2(g) ΔH = -41 kJ mol-1 Which of the following will cause a shift in the position of equilibrium? (1) Adding a catalyst (2) Changing the temperature (3) Changing the volume (1) only (2) only (1) and (3) only (2) and (3) only

(2) only

Nitrosyl bromide decomposes according to the following equation.2NOBr (g) 2NO (g) + Br2 (g)A sample of NOBr (0.64 mol) was placed in a 1.00-L flask containing no NO or Br2. At equilibrium the flaskcontained 0.46 mol of NOBr. How many moles of NO and Br2, respectively, are in the flask at equilibrium? 0.46, 0.23 0.18, 0.090 0.46, 0.46 0.18, 0.360 0.18, 0.18

0.18, 0.090

In the coal-gasification process, carbon monoxide is converted to carbon dioxide via the following reaction:CO (g) + H2O (g) CO2 (g) + H2 (g)In an experiment, 0.35 mol of CO and 0.40 mol of H2O were placed in a 1.00-L reaction vessel. At equilibrium,there were 0.19 mol of CO remaining. Keq at the temperature of the experiment is ___________. 0.75 1.0 5.47 1.78 0.56

0.56

Acetic acid is a weak acid that dissociates into the acetate ion and a proton in aqueous solution: HC2H3O2 (aq) <=> C2H3O2- (aq) + H+ (aq) At equilibrium at 250C a 0.100 M solution of acetic acid has the following concentrations: [HC2H3O2] = 0.0990 M, [C2H3O2-] = 1.33 ˛ 10-3 M, and [H+] = 1.33 ˛ 10-3 M. The equilibrium constant, Keq, for the ionization of acetic acid at 250C is __________. 5.7*104 1.79*10-5 1.75*10-7 5.71*106 0.100

1.79*10-5

For the reaction C(s) + CO2(g) <=> 2CO(g), Kc = 0.122 at 1100K. What is the value of Kp for this reaction at 1100K? 1.35x10-3 0.122 11.0 945 1.12x103

11.0

At 1000K, the equilibrium constant for the reaction : 2NO (g) + Br2(g) <=> 2NOBr (g) is Kp: 0.013. Calculate the Kp for the reverse reaction, 2NOBr (g) <=> 2NO (g) + Br2 (g) 0.99 1.1 0.013 1.6*10-4 77

77

Consider the following equilibrium system: N2H4(g) + O2(g) -----.> N2 + 2H2O(g) Which of the following actions can cause the position of equilibrium to shift to the right? Adding N2H4(g) Adding H2O(g) Removing N2H4(g) Removing O2(g)

Adding N2H4(g)

Consider the following equilibrium system: 2KClO3(s) <=> 2KCl(s) + 3O2(g) Which of the following actions will cause the position of equilibrium to shift to the left? Adding O2(g) Adding KCl(s) Removing KClO3(s) Removing KCl(s)

Adding O2(g)

Consider the following equilibrium system: PCl3(g) + Cl2(g) <=> PCl5(g) ΔH < 0 Which of the following will NOT cause the position of equilibrium to shift to the right? Adding more Cl2(g) Adding a catalyst Increasing the pressure Decreasing the temperature

Adding a catalyst

In which of the following systems will the position of equilibrium shift to the left upon an increase in pressure, but to the right upon an increase in temperature? CO2(g) + H2(g) <=> CO(g) + H2O(g)ΔH > 0 C2H6(g)<=> C2H4(g) + H2(g) ΔH > 0 C2H4(g) + H2O(g) <=> C2H5OH(g) ΔH < 0 2SO2(g) + O2(g) <=> 2SO3(g) ΔH < 0

C2H6(g)<=> C2H4(g) + H2(g) ΔH > 0

Consider the following equilibrium system: CO2(g) + H2(g) <=> CO(g) + H2O(g) Which of the following, when added to the system above, would result in a decrease in [H2O(g)] relative to the previous equilibrium? CO(g) CO2(g) H2(g) H2O(g)

CO(g)

In which of the following would the position of the equilibrium NOT be affected by a volume change at constant temperature? 2NF2(g) <=> N2F4(g) C2H6(g)<=> C2H4(g) + H2(g) 2NOCl(g) <=> 2NO(g) + Cl2(g) CO(g) + H2O(g)<=>H2(g) + CO2(g)

CO(g) + H2O(g)<=>H2(g) + CO2(g)

Consider the following equilibrium system: Ca(OH)2(s) <=> Ca2+(aq) + 2OH-(aq) Adding which of the following substances will cause the equilibrium concentration of Ca2+(aq) ions to increase? H2O(l) HCl(aq) KOH(s) Ca(OH)2(s)

HCl(aq)

Consider the following equilibrium system: N2(g) + 3H2(g) <=> 2NH3(g) ΔH < 0 Which of the following sets of conditions will favour the formation of the product? Low pressure and low temperature Low pressure and high temperature High pressure and high temperature High pressure and low temperature

High pressure and low temperature

Phosgene (COCl2(g)) is manufactured by passing carbon monoxide and chlorine through a bed of carbon which acts as a catalyst. CO(g) + Cl2(g)<=>COCl2(g) ΔH < 0 Which of the following sets of conditions will favour the formation of phosgene? Low pressure and low temperature Low pressure and high temperature High pressure and low temperature High pressure and high temperature

High pressure and low temperature

Consider the following system at fixed pressure: CH4(g) + H2O(g)<=> CO(g) + 3H2(g) ΔH > 0 What is the effect of a small increase in temperature on the rate of the forward reaction (Rf), rate of the backward reaction (Rb), and the equilibrium constant (Kc)? Rf Rb Kc Lower higher lower Higher lower unchanged Higher higher higher Higher higher lower

Higher higher higher

The hydrogen used in the Haber process is made by the following reaction: CH4(g) + H2O(g) <=>CO(g) + 3H2(g) ΔHO = +206 kJ Which of the following sets of conditions will favour the formation of hydrogen? Low pressure and low temperature Low pressure and high temperature High pressure and low temperature High pressure and high temperature

Low pressure and high temperature

In which of the following reactions would increasing pressure at constant temperature not change the concentrations of reactants and products, based on Le Ch^atelier's principle? N2 (g) + 3H2 (g) <=> 2NH3 (g) 2N2 (g) + O2 (g) <=> 2N2O (g) N2 (g) + 2O2 (g) <=> 2NO2 (g) N2O4 (g) <=> 2NO2 (g) N2 (g) + O2 (g) <=> 2NO (g)

N2 (g) + O2 (g) <=> 2NO (g)

The expression for Kp for the reaction below is __________. 4CuO (s) + CH4 (g) <--> CO2 (g) + 4Cu (s) + 2H2O (g) PCH4 / PCO2PH2^2 [Cu]PCO2PH2O^2 / [CuO]^4 PCH4 PCO2PH2O^2 / PCH4 PCO2PH2O^2 / PCuO PCH4 / PH2O^2PCO2

PCO2PH2O^2 / PCH4

In which of the following systems will the position of equilibrium shift to the right when the pressure is increased at constant temperature? CaCO3(s)<=> CaO(s) + CO2(g) 2NO2(g) <=>2NO(g) + O2(g) H2(g) + I2(g)<=>2HI(g) PCl3(g) + Cl2(g)<=>PCl5(g)

PCl3(g) + Cl2(g)<=>PCl5(g)

Consider the following equilibrium system: CO(g) + H2O(g) <=> CO2(g) + H2(g) Which of the following actions would cause the concentration of H2(g) to decrease? Adding CO(g) Adding H2O(g) Removing CO2(g) Removing H2O(g)

Removing H2O(g)

How is the reaction quotient used to determine whether a system is at equilibrium? The reaction is at equilibrium when Q < Keq. The reaction is at equilibrium when Q > Keq. At equilibrium, the reaction quotient is undefined. The reaction quotient must be satisfied for equilibrium to be achieved The reaction is at equilibrium when Q = Keq.

The reaction is at equilibrium when Q = Keq

What is the expression for Kc for the reaction: C(s) + H2O(g) <=> CO(g) + H2(g) {[CO]+[H2]}/{[C]+[H2O]} [CO][H2]/[C][H2O] {[CO]+[H2]}/[H2O] [CO][H2]/[H2O] [CO][H2]

[CO][H2]/[H2O]

Sulfur dioxide combines with O2 in the presence of a catalyst as represented by the equation 2SO2(g) + O2(g) mc006-1.jpg 2SO3(g) Suppose 0.10 mol of SO2 and 0.10 mol of O2 are added to a 1-L vessel. At equilibrium, which of the following conditions must be true? [O2] = 2[SO3] [SO2] = [O2] [SO2] > [O2] [SO2] < [O2] [SO2] = [O2] = [SO3]

[SO2] < [O2]

Consider the following equilibrium: 4NH3 (g) + 5O2 (g) <=> 4NO(g) + 6H2O(g) + energy Which of the following will cause the equilibrium to shift to the left? adding H2O(g) removing some NO(g) increasing the volume decreasing the temperature

adding H2O(g)

Which one of the following will change the value of an equilibrium constant? adding other substances that do not react with any of the species involved in the equilibrium varying the initial concentrations of reactants changing temperature varying the initial concentrations of products changing the volume of the reaction vessel

changing temperature

Consider the following equilibrium system: Co2+(aq) + 4Cl-(aq)<=> CoCl 2-(aq) pink blue When the temperature is increased, the solution turns dark blue. It can be deduced that the forward reaction is exothermic and the value of Kc has increased. exothermic and the value of Kc has decreased. endothermic and the value of Kc has increased. endothermic and the value of Kc has decreased.

endothermic and the value of Kc has increased.

For the endothermic reaction 2CO2(g) + N2(g) mc100-1.jpg 2NO(g) + 2CO(g), the conditions that favor maximum conversion of the reactants to products are high temperature and low pressure. high temperature, pressure being unimportant. low temperature and low pressure. low temperature and high pressure. high temperature and high pressure.

high temperature and low pressure.

The effect of a catalyst on an equilibrium is to __________. increase the rate at which equilibrium is achieved without changing the composition of the equilibrium mixture increase the rate of the forward reaction only shift the equilibrium to the right increase the equilibrium constant so that products are favored slow the reverse reaction only

increase the rate at which equilibrium is achieved without changing the composition of the equilibrium mixture

At equilibrium, __________. the rates of the forward and reverse reactions are equal the rate constants of the forward and reverse reactions are equal all chemical reactions have ceased the value of the equilibrium constant is 1 the limiting reagent has been consumed

the rates of the forward and reverse reactions are equal

The value of equilibrium constant for a gaseous reaction will change when a catalyst is used. the temperature changes. the concentrations of products change. the volume changes.

the temperature changes.