Chapter 15
Write the equilibrium expression for KC for the following reaction:
a) 2 O3 (g) ↔ 3 O2 (g)
b) 2 NO (g) + Cl2 (g) ↔ 2 NOCl (g)
c) Ag+ (aq) +2 NH3 (aq) ↔ Ag(NH3)2+ (aq)
a) [O2]3 / [O3]2
b) [NOCl]2 / [NO]2 [Cl2]
c) [Ag(NH3)2+] / [Ag+] [NH2]2
Consider the equilibrium:
2 SO2 (g) + O2 (g) ↔ 2 SO3 (g)
If 0.200 mol SO3 (g) is placed in a 0.500 L container, it is found that 0.050 mole of O2 (g) is in the container at equilibrium. Determine Keq
10
Calculate [OH-] and indicate whether the solution is acidic, basic, or neutral.
[H+] = 7.9 x 10-3
[OH-] = 1.27 x 10-12 M
Basic
What are the 7 strong acids?
HCl, HBr, HI, HNO3, H2SO4, HClO3, HClO4
Consider the equilibrium:
N2O4 (g) ↔ 2 NO2 (g) ∆HO = 58.0 kJ
In which direction will the equilibrium shift when
a) N2O4 is added
b) NO2 is removed
c) the pressure is increased by addition of N2 (g)
d) the volume is increased
e) the temperature is decreased
a) right
b) right
c) no shift
d) right
e) left
For the formula:
N2 (g) + 3 H2 (g) ↔ 2 NH3 (g)
KC = 9.60 at 300OC. Calculate KP for the reaction at this temperature.
4.34 x 10-3
At 985OC, the equilibrium constant, KC, for the reaction:
H2 (g) + CO2 (g) ↔ H2O (g) + CO (g), is 1.63. If 2.00 moles each of H2 and CO2 are placed in a 1.00 L container and allowed to come to equilibrium, determine the equilibrium concentrations of the 4 chemicals.
[H2] = 0.88 M
[CO2] = 0.88 M
[H2O] = 1.12 M
[CO] = 1.12 M
Calculate [OH-] and indicate whether the solution is acidic, basic, or neutral.
[H+] = 6.3 x 10-10
[OH-] = 1.59 x 10-5 M
Acidic
b) Given that Kb for ammonia is 1.8 x 10-5 and that for hydroxylamine is 1.1 x 10-8, which is the stronger base?
a) acetic acid (larger Ka = stronger acid)
b) ammonia (larger Kb = stronger base)
For the reaction:
PCl5 (g) ↔ PCl3 (g) + Cl2 (g) ∆HO = 87.9 kJ
in which direction will the equilibrium shift when
a) Cl2 (g) is removed
b) the temperature is decreased
c) the volume of the reaction system is increased
d) PCl3 (g) is added
a) right
b) left
c) right
d) left
Given the reactions:
HF (aq) ↔ H+ (aq) + F- (aq) KC = 6.8 x 10-4
H2C2O4 (aq) ↔ 2 H+ (aq) + C2O42- (aq) KC = 3.8 x 10-6
determine the value of KC for the reaction:
2 HF (aq) + C2O42- (aq) ↔ 2 F- (aq) + H2C2O4 (aq)
0.12
Consider the reaction:
NH3 (aq) + H2O (l) ↔ NH4+ (aq) + OH- (aq)
Keq = 1.8 x 10-5
What is the [OH-] in a 0.100 M solution of NH3 when it reaches equilibrium?
1.3 x 10-3 M
Calculate the pH of each of the following acid solutions.
a) 0.0534 M HNO3
b) 0.271 g of HClO4 in 1.90 L of solution
c) 5.00 mL of 1.00 M HCl diluted to 0.690 L
d) a mixture formed by adding 50.0 mL of 0.020 M HCl to 125 mL of 0.010 M HI
a) 1.27
b) 2.85
c) 2.14
d) 1.88
a) HNO2 or HNO3
b) H2O or H2S
a) HNO3 (more oxygen)
b) H2S (acidity increases as you go to the right and down the periodic table)
What is the conjugate base for the following:
a) CN-
b) SO42-
c) H2O
a) HCN
b) HSO4-
c) H3O+
After a mixture of hydrogen and nitrogen gases in a reaction vessel is allowed to attain equilibrium at 472OC, it is found to contain 7.38 atm H2, 2.46 atm N2, and 0.166 atm NH3. From these data, calculate the equilibrium constant KP for the reaction:
N2 (g) + 3 H2 (g) ↔ 2 NH3 (g)
1.79 x 10-5
Calculate the equilibrium constant, Keq, for the following reaction at 25OC, if [NO] = 0.106 M, [O2] = 0.122 M, and [NO2] = 0.129 M.
2 NO (g) + O2 (g) ↔ 2 NO2 (g)
12.1
Calculate the pH of a solution formed by mixing 55 mL of 0.20 M NaHCO3 with 65 mL of 0.15 M Na2CO3.
10.20
What is the Lewis Acid and Lewis Base in the following equation:
NH3 + BF3 ↔ NH3BF3
LB = NH3
LA = BF3
What is the conjugate acid for the following:
a) HClO4
b) H2S
c) PH4+
a) ClO4-
b) HS-
c) PH3
At 1000 K the value of KP for the reaction
2 SO3 (g) ↔ 2 SO2 (g) + O2 (g)
is 0.338. Calculate the value for QP, And predict the direction in which the reaction proceeds toward equilibrium if the initial partial pressures are
PSO3 = 0.16 atm; PSO2 = 0.41 atm; PO2 = 2.5 atm
QP = 16
QP > KP so the rxn proceeds from right to leftFor the equilibrium:
Br2 (g) + Cl2 (g) ↔ 2 BrCl (g)
at 400 K, KC = 7.0. If 0.25 mol of Br2 and 0.55 mol of Cl2 are introduced into a 2.5-L container at 400 K, what will be the equilibrium concentrations of Br2, Cl2, and BrCl?
[Br2] = 0.019 M
[Cl2] = 0.12 M
[BrCl] = 0.13 M
How many grams of sodium lactate (NaC3H5O3) should be added to 1.00 L of 0.150 M lactic acid (HC3H5O3) to form a buffer solution with pH 2.90? Assume that no volume change occurs when NaC3H5O3 is added.
1.9 g
What is the Lewis Acid and Lewis Base in the following equation:
Ag+ + Br2 ↔ AgBr2
LB = Ag+
LA = Br2
A 30.0 mL sample of 0.150 M propanoic acid (a monoprotic acid C3H7COOH, Ka = 1.3 x 10-5) is titrated with 0.300 M KOH. Calculate the following:
a. the initial pH of the acid
b. the equivalence point volume of the titration
c. the pH after adding 5.00 mL of KOH
d. the pH at the equivalence point
a. 5.71
b. 15.0 mL
c. 4.59
d. 8.94