Chapter 12 - Homework Answers (Equilibrium)

Chapter 12 Homework Answers

When the following equation is balanced using the smallest possible integers, what is the exponent of N2O in the reaction quotient expression?

N2O + H2 ó NH3 + H2O
Its balanced equation is
(1)N2O + 4H2 ó 2NH3 + H2O
there is a 1 in front of the N2O when it is balanced therefore the exponent is 1

N2O(g) + H2(g) ó NH3(g) + H2O(g)
____1_____

In a 1.0 L vessel, at 298 K, 0.761 M A (g) and 0.916 M B (g) react to form 0.503 M C (g). What is the value of the equilibrium constant for this reaction at 298K?
A (g) + B (g) ↔ C (g)
a.
4.72
b.
0.212
c.
0.722
d.
0.00242
e.
1.24
Take C and subtract it from A & B, now A=.258 and B=.413
Use C/AB = Products/Reactants = 4.72
In a 1.0 L vessel, at 298 K, 0.0323 mol COCl2 (g) is added. What is the equilibrium concentration of CO 
if Kc = 1.2 x 103 at this temperature?
CO (g) + Cl2 (g) ↔ COCl2 (g)
a.
0.0000269
b.
0.000475
c.
0.000932
d.
0.000240
e.
0.0485
Since we start out with the product we have to work our way backerds.
[C] = 0.0323-x because it’s becoming equalized with [A]&[B]
[A] and [B] are (0+x) respectively.
Make equation [C]/[A][B] = à 0.0323-x/(0+x)(0+x) = 1200 Solve for x and you get…
0.000475 maybe book made error?


In a 1.0 L vessel, at 698 K, 0.844 M H2 (g) and 0.844 M I2 (g) are combined. What is the concentration of HI (g) at equilibrium? Kc = 54.3 at 698 K.
H2 (g) + I2 (g) ↔ 2 HI (g)
a.
1.33
b.
1.69
c.
0.198
d.
0.664
e.
1.25






H2 + I2 <-------------> 2HI 
initially.... 
0.844 + 0.844 <------------> 0 
at equilibrium... 
(0.844 - x ) + ( 0.844 - x ) <------------> 2x 
conc. of H2 at equilibrium = 0.844-x 
conc. of I2 at equilibrium = 0.844 - x 
conc. of HI at equilibrium = 2x 

Kc = [HI]^2 / [H2][I2] = 2x^2 / ( 0.844 - x ) ( 0.844 - x ) 
54.3 = 4x^2 / (0.844 -x)^2 
54.3 = 4x^2 / ( 0.844^2 + x^2 - 2 X 0.844x) 
54.3 = 4x^2 / ( 0.712 + x^2 - 1.688x ) 
54.3 ( 0.712 + x^2 - 1.688x ) = 4x^2 
38.662 + 54.3x^2 - 91.658x = 4x^2 
54.3x^2 - 4x^2 - 91.658x + 38.662 = 0 
50.3x^2 - 91.658x + 38.662 = 0 ... 
Solve the quadratic equation
x = 0.663 and x = 1.159 
as x cant be greater than 0.844 as otherwise concentration will be negative 
so conc of HI at equilibrium = 2x = 2 X 0.663 = 1.33 M

If 1.00 mole of PCl3 and 1.00 mole of Cl2 are placed in a 5.00-L container, the following equilibrium is reached.
PCl3 (g) + Cl2 (g) ⇔ PCl5 (g) Kc = 10.0 at the temperature maintained.
What is the equilibrium concentration of [PCl3] in mol/L? .2 is from mol per L, 1/5 mol/L
a.
0.12
b.
0.13
c.
0.14
d.
0.11
e.
0.10






_________________PCl5<------>PCl3__+_Cl... 
Initial concentration_0M_______.2M_____.2M 
Reaction__________+x________-x_______-x 
Equilibrium________ x________.2-x_____.2-x 
Now you can plug your equilibrium values into your equilibrium equations. 
10 = x/(.2-x)(.2-x) 
10 = x/(.04 - .4x + x^2) 
then .4 -4x + 10x^2 = x .4 - 5x + 10x^2 = 0 
Now that you can use the quadratic equation to solve for x. 
You should get x = .4 and .1 
Now if you use .4 for x, you will have negative values for your PCl3 and Cl2 which is impossible. 
So x has to be .1 
Now solve for your concentration of PCl3 
PCl3 = .2 - x 
.2 - .1 = .1M


The solubility of lead(II) chloride is 0.45 g/100 mL of solution. What is the Ksp of PbCl2?
a.
4.9 × 10¯2
b.
1.7 × 10¯5
c.
8.5 × 10¯6
d.
4.2 × 10¯6
e.
< 1.0 × 10¯6
First, convert g/mL to mol/L by doing the table (YOU MUST DO THE TABLE)
Then split up the Pb and the Cl2 and balance:  PbCl2àPb2+ + 2Cl-
Set up the equation like this Ksp = [Pb2+][Cl-]2 . Now apply mol/L to each respectively.

For [Pb2+] = 1(0.0162 mol/L)
For [Cl-]2  = 2(0.0162 mol/L)2

And solve (0.0162)*(2(0.0162))^2 = 0.0000169 mol/L OR 1.7 * 10^-5 mol/L

Which of the following substances has the greatest solubility in water?
a.
PbI2, Ksp = 7.9 × 10¯9
b.
BaF2, Ksp = 1.5 × 10¯6
c.
Ca(OH)2, Ksp = 6.5 × 10¯6
d.
Zn(IO3)2, Ksp = 3.9 × 10¯6
e.
Ag2SO4, Ksp = 1.5 × 10¯5








What is the pH of a 0.0100 M sodium benzoate solution? Kb (C7H5O2¯) = 1.5 × 10¯10
a.
0.38
b.
5.91
c.
8.09
d.
9.82
e.
13.62






x=sqrt((0.01M) * (1.5 * 10^-10))  Then take the –log of the answer (.000001225)

And you get 5.912 (WHICH IS NOT THE ANSWER) this is only the pOH.
To get the pH take 14 - 5.912 = 8.0881 
Aqueous solutions of phosphoric acid and sodium nitrite are combined, and the following equilibrium is established.
H3PO4(aq) + NO2¯(aq)  ó H2PO4¯(aq) + HNO2(aq)


The equilibrium constant Kc for this reaction is greater than one. Based on this information, which of the following statements is correct?
a.
The nitrite anion is a weaker base than the dihydrogen phosphate anion.
b.
Nitrous acid is a weaker acid than water.
c.
Phosphoric acid is a weaker acid than nitrous acid.
d.
The dihydrogen phosphate anion is a stronger acid than nitrous acid.
e.
Phosphoric acid is a stronger acid than nitrous acid.

If NaCl is added to a saturated solution of AgCl, the equilibrium will shift back towards the reactants; and the solubility of AgCl will decrease.
1.
True
2.
False
Well if AgCl is already saturated then yeah.
What would be the effect of decreasing the temperature on the following reaction?
C2H2(g) + H2O(g) <=> CH3CHO(g) DHrxn = -15 1 kJ
a.
[CH3CHO] would increase
b.
[CH3CHO] would decrease
c.
[CH3CHO] would stay the same

The equilibrium constant for the following reaction is given. Assuming that the forward and reverse reactions can be written as elementary steps, which statement below is true for this reaction at equilibrium?
A ⇔ B + C Kc = 150
a.
The rate constants for the forward and reverse reactions are identical at equilibrium.
b.
The rate constant for the reverse reaction is 150 times greater than that for the forward reaction.
c.
The rate constant for the forward reaction is smaller than that for the reverse reaction.
d.
The rate constant for the forward reaction is 150 times greater than that for the reverse reaction.
e.
The rate constants for this reaction cannot be determined based on the equilibrium constant.

The term "strong acid" refers to any acid of 0.100 M concentration or higher.
1.
True
2.
False
A strong acid is one that completely dissociates in water or a solution.

 At a certain temperature, the equilibrium mixture of the reaction PCl5 (g) ⇔ PCl3 + Cl2 (g) has PCl5 = 1.50 atm. PCl3 = 0.10 atm and PCl2= 7.50 atm Calculate the value of Kp at this temperature.
a.
0.77
b.
0.50
c.
2.0
d.
1.3
e.
1.0






Assuming  Cl2 is meant to be PCl2 then Kp is a normal equilibrium problem.
(0.10 * 7.50)/1.5 Products over reactants.
An equilibrium mixture of NO (g), O2 (g) and NO2 (g) is allowed to expand from 1.0 L to 2.0 L at a constant temperature. 
2 NO (g) + O2 (g) ⇔ 2 NO2 (g)
Which of the following statements is correct?
                                                                                                   NO CLUE
a.
Concentrations of all three gases are unchanged.
b.
The value of Kp would decrease.
c.
The number of moles of NO2 would increase.
d.
The number of moles of O2 would increase.
e.
The number of moles of all three gases are unchanged.


For the reaction: H2 + Br2 ⇔ 2 HBr, Kc = 7.5 × 102 at a certain temperature.
1.00 mole HBr is placed in 5.0 L flask at a certain temperature. What is the concentration of HBr at equilibrium?
a.
0.19
b.
0.81
c.
0.01
d.
0.94
e.
0.03
Do the ICE table and REMEMBER HBR IS SQUARED.




For the reaction: H2 + Br2 ⇔ 2 HBr, Kc = 7.5 × 102 at a certain temperature.
If 1 mole each of H2 and Br2 are placed in 1 L flask, what is the concentration of H2 at equilibrium?
a.
0.46
b.
0.04
c.
0.93
d.
0.96
e.
0.07


What is the molar solubility of CaF2 (Ksp = 3.9 ∗ 10-11)?
1.
2.14 ∗ 10-4 M
2.
6.24 ∗ 10-6 M
3.
9.27 ∗ 10-5 M
4.
4.41 ∗ 10-6 M

The lower the pH of a weak acid, the:
1.
higher the dissolved H2(g) concentration.
2.
none of the above
3.
higher the Ka of the acid.
4.
higher the concentration of the weak acid.

A solution is prepared by adding 0.10 mol of sodium fluoride, NaF, to 1.00 L of water. Which statement about the solution is correct?
a.
The solution is basic.
b.
The solution is neutral.
c.
The solution is acidic.
d.
The concentrations of fluoride ions and sodium ions will be identical.
e.
The concentration of fluoride ions will be greater than the concentration of sodium ions.

In a dynamic equilibrium the rates of the forward and reverse reactions go to zero once the equilibrium is reached. Dynamic means it’s going back and forth to an extent “forever”
1.
False
2.
True

In a dynamic equilibrium:
1.
the rate of the forward reaction goes to zero
2.
the rates of the forward and reverse reactions become equal
3.
the reaction begins to favor the reverse direction
4.
the rate of the forward and reverse reactions go to zero


If a reaction is in a state where Q > K,
1.
the rate of the reaction will always double.
2.
more products will form.
3.
the reaction will remain in a steady-state.
4.
more reactants will form.

The synthesis of the pesticide thionyl chloride (OSCl2) proceeds according to:
SO3(g) + SCl2(l) ó OSCl2(l) + SO2(g)
If ΔG0 = -106 kJ/mol for this reaction at 298K, what is the Keq at this temperature? Recall: R = 8.314 J mol-1 K-1.
1.
3.81 ∗ 1018
2.
7.21 ∗ 1012
3.
3.50 ∗ 1014
4.
1.19 ∗ 1020

Write the ion product expression for calcium phosphate, Ca3(PO4)2.
a.
[Ca2+][PO43-]
b.
[Ca2+]2[PO43-]3
c.
[Ca2+]3[PO43-]2 <<<<------ This One
d.
[Ca2+][PO43-]
[Ca3(PO4)2
e.
None of these choices is correct.



Write the ion product expression for silver sulfide, Ag2S.
a.
[Ag+][S2-]
b.
[Ag+][S2-]2
c.
[Ag+]2[S2-]
[Ag2S(s)]
d.
        1      .
[Ag+][S2-]2
e.
[Ag+]2[S2-]


The lower the pH of a weak acid, the:
1.
higher the Ka of the acid.
2.
higher the dissolved H2(g) concentration.
3.
higher the concentration of the weak acid.
4.
none of the above

Consider the following exothermic reaction:
N2 (g) + 3 H2 (g) ⇔ 2 NH3 (g)
Which of the following changes would not increase the amount of NH3 produced from given quantities of 
N2 and H2?
a.
an increase in P
b.
an increase in T
c.
a decrease in V
d.
removing some NH3 and reestablishing equilibrium
e.
none of these

Sodium bicarbonate undergoes thermal decomposition according to
2 NaHCO3(s) ó Na2CO3(s) + CO2(g) + H2O(g)
What happens when some NaHCO3 is added
a.
[CO2] increases
b.
[CO2] decreases
c.
[CO2] stays the same

Sodium bicarbonate undergoes thermal decomposition according to
2 NaHCO3(s) ó Na2CO3(s) + CO2(g) + H2O(g)
What happens when some dry ice (CO2(s)) is added and converts partly to CO2(g)?
a.
[H2O] stays the same
b.
[H2O] decreases
c.
[H2O] increases


Products appear in the numerator of the reaction quotient
1.
False
2.
True

Kp for the reaction H2 (g) + I2 (g) ⇔ 2 HI(g) is 54.3 at 698°C. What is the value of Kc at this temperature?
(R = 0.0821 L atm/mol K)
a.
85.6
b.
1.8 × 10−2
c.
2.3 × 10−4
d.
4.33 × 103
e.
54.3


Which of the following substances has the greatest solubility in water?
a.
Ba(IO3)2, Ksp = 1.5 × 10¯9
b.
PbF2, Ksp = 3.6 × 10¯8
c.
SrSO4, Ksp = 3.2 × 10¯7
d.
CuCl, Ksp = 1.9 × 10¯7
e.
CdS, Ksp = 1.0 × 10¯24


What is the pH of a 0.0250 M pyridine solution? (Kb = 1.5 ∗ 10-9)?
1.
13.1
2.
8.79
3.
5.21
4.
4.72

Calculate the solubility of zinc hydroxide, Zn(OH)2, in 1.00 M NaOH.
Ksp = 3.0 × 10¯16 for Zn(OH)2, Kf = 3.0 × 1015 for Zn(OH)42¯
a.
0.60 M
b.
0.52 M
c.
0.37 M
d.
0.32 M
e.
0.24 M

Sodium bicarbonate undergoes thermal decomposition according to
2 NaHCO3(s) ó Na2CO3(s) + CO2(g) + H2O(g)
What happens when 0.20 atm of argon gas is added
a.
[CO2] stays the same
b.
[CO2] decreases
c.
[CO2] increases

Which of following species is amphoteric?
1.
C4H10
2.
NaOH
3.
H2O
4.
H2SO4
Because, it can act as an acid and a base by either giving or receiving a hydrogen atom.
If the equilibrium concentrations found in the reaction:
2 A(g) + B(g) ⇔ 2 C(g),
are A = 0.35 M, B = 0.32 M, and C = 0.46 M. Calculate Kc as a decimal number (e.g., 1.234) with 3 decimal places and do not include units.
___0.185___


The higher the Ksp of the salt, the less soluble the salt.
1.
False
2.
True

Calculate the solubility of silver oxalate, Ag2C2O4, in pure water. Ksp = 1.0 × 10¯11
a.
1.4 × 10¯4 M
b.
5.4 × 10¯5 M
c.
8.2 × 10¯5 M
d.
3.2 × 10¯6 M
e.
2.5 × 10¯12 M


What is the pH of a 0.165 M CH3COOH solution (Ka = 1.75 ∗ 10-5)?
1.
2.770
2.
8.474
3.
3.188
4.
5.721

What is the pH of a 0.050 M triethylamine, (C2H5)3N, solution?
Kb for triethylamine is 5.3 × 10¯4.
a.
11.69
b.
5.32
c.
< 2.0
d.
2.31
e.
8.68

The equilibrium constant for the following reaction is given. Assuming that the forward and reverse reactions can be written as elementary steps, which statement below is true for this reaction at equilibrium?
A ⇔ B + C Kc = 150
a.
The rate constants for the forward and reverse reactions are identical at equilibrium.
b.
The rate constant for the forward reaction is 150 times greater than that for the reverse reaction.
c.
The rate constant for the reverse reaction is 150 times greater than that for the forward reaction.
d.
The rate constant for the forward reaction is smaller than that for the reverse reaction.
e.
The rate constants for this reaction cannot be determined based on the equilibrium constant.

Which Keq value indicates a reaction most favoring the formation of products?
1.
K = 1.7 ∗ 10-6
2.
K = 4.99 ∗ 106
3.
All these Keq favor reactants
4.
K = 5.31 ∗ 103
5.
K = 8.2 ∗ 10-3

Determine the value of Kc for the following reaction given the Kp.
CO (g) + Cl2 (g) ⇔ COCl2 (g) Kp = 15.0 at 300°C (R = 0.0821 L•atm/molK)
a.
706
b.
1.42 × 10−3
c.
0.319
d.
369
e.
3.14

Use the following information to calculate the solubility product constant, Ksp, for PbCl2. A saturated solution of PbCl2 in water was prepared and filtered. From the filtrate, 1.0 L was measured out into a beaker and evaporated to dryness. The solid PbCl2 residue recovered in the beaker amounted to 0.0162 moles.
a.
Ksp = 6.9 × 10¯8
b.
Ksp = 4.3 × 10¯6
c.
Ksp = 1.7 × 10¯5
d.
Ksp = 2.6 × 10¯4
e.
Ksp = 3.2 × 10¯2

Consider the solubility of BaSO4. If Ba(NO3)2 is added to the solution, the solubility of the barium sulfate:
1.
is unaffected
2.
is moot because barium sulfate is a strong electrolyte
3.
increases
4.
decreases

Given the reaction shown below at equilibrium, how will addition of 0.10 M K3PO4 solution affect the equilibrium? Answer r for shift to the right, l for shift to the left or n for no change.
Ca3(PO4)2(s) ó 3Ca2+(aq) + 2PO43-(aq)
____L___



Which of following species is a Brønsted-Lowry base?
1.
C4H10
2.
CaCl2
3.
NaOH
4.
H2SO4

A lab technician adds 0.015 mol of KOH to 1.00 L of 0.0010 M Ca(NO3)2. Ksp = 6.5 × 10¯6 for Ca(OH)2. Which of the following statements is correct?
a.
Calcium hydroxide precipitates until the solution is saturated.
b.
The solution is unsaturated and no precipitate forms.
c.
The concentration of calcium ions is reduced by the addition of the hydroxide ions.
d.
One must know Ksp for calcium nitrate to make meaningful predictions on this system.
e.
The presence of KOH will raise the solubility of Ca(NO3)2.

Picric acid has been used in the leather industry and in etching copper. However, its laboratory use has been restricted because it dehydrates on standing and can become shock sensitive. It has an acid dissociation constant of 0.42. What is the [H3O+] for a 0.20 M solution of picric acid?
a.
0.022 M
b.
0.052 M
c.
0.15 M
d.
0.29 M
e.
None of these choices is correct.

Consider the dissolution of MnS in water (Ksp = 3.0 × 10¯14).
MnS(s) + H2O(l)  ó Mn2+(aq) + HS¯(aq) + OH¯(aq)
How is the solubility of manganese(II) sulfide affected by the addition of aqueous potassium hydroxide to the system?
a.
The solubility will be unchanged.
b.
The solubility will decrease.
c.
The solubility will increase.
d.
The amount of KOH added must be known before its effect can be predicted.
e.
The pKa of H2S is needed before a reliable prediction can be made.

The term "strong acid" refers to any acid of 0.100 M concentration or higher.
1.
False
2.
True

For the system 2A (g) + B( g) ⇔ 2C (g), if the initial concentration of pure C is 1.00 M, the equilibrium concentration is 0.40 M. What is the value of Kc for the equilibrium as written?
a.
0.67
b.
2.2
c.
1.5
d.
5.0
e.
0.45

Hydroxylamine, HONH2, readily forms salts such as hydroxylamine hydrochloride which are used as antioxidants in soaps. Hydroxylamine has Kb of 9.1 × 10¯9. What is the pH of a 0.025 M HONH2 solution?
1.
4.82
2.
9.18
3.
11.10
4.
2.90
5.
9.91

Which of these best describe the direction the following reaction (in a 5.0 L flask) will proceed if more calcium oxide is added to the system?
CaCO3 (s) ⇔ CaO (s) + CO2 (g) Kp = 1.9 x 10−23
a.
to the right
b.
to the left
c.
The equilibrium position will not shift because calcium oxide is a solid.
d.
The equilibrium constant gets smaller to reflect the added calcium oxide.
e.
More information is needed to answer this question.


If the equilibrium total pressure of the system below is 1.0 atm in a 1.0 L flask, what is the partial pressure of N2O4?
N2O4 (g) → 2 NO2 (g) Kp = 0.660 at 319 K
a.
0.50 atm
b.
0.45 atm
c.
0.55 atm
d.
0.27 atm
e.
0.66 atm

The solubility of calcium chromate is 1.56 × 10¯3 g/100 mL of solution. What is the Ksp for CaCrO4?
a.
2.4 × 10¯4
b.
1.5 × 10¯5
c.
7.6 × 10¯6
d.
1.0 × 10¯8
e.
< 1.0 × 10¯8

Which of the following is most likely to precipitate Cl1- ions?
1.
NaCl(s) à Na1+(aq) + Cl1-(aq)
2.
PbCl2(s) à Pb2+(aq) + 2 Cl1-(aq)          Ksp = 1.75 ∗ 10-5
3.
AgCl(s) à Ag1+(aq) + Cl1-(aq)          Ksp = 1.8 ∗ 10-10
4.
Hg2Cl2(s) à 2 Hg1+(aq) + 2 Cl1-(aq)          Ksp = 1.1 ∗ 10-18

At a certain temperature, Kp = 25 for the following reaction:
NH4Cl (s) ⇔ NH4 (g) + HCl (g)
What is the total pressure, in atm, of the gases at equilibrium?
a.
10
b.
5
c.
25
d.
6.3 × 102
e.
More information is required.

Consider the solubility of BaSO4. If Ba(NO3)2 is added to the solution, the solubility of the barium sulfate:
1.
increases
2.
is unaffected
3.
is moot because barium sulfate is a strong electrolyte
4.
decreases

Potassium hydrogen phthalate (KHP) concentrations can be determined through titrating samples of KHP (a monoprotic acid) with bases such as NaOH in the presence of an indicator such as phenolphthalein. The indicator is colorless in an acidic solution and turns pink in an alkaline solution. Thus we can establish an equilibrium for the phenolphthalein as such:

HIn + H2O <=> In- + H3O+

If the HIn species is the "acid color" or clear for the phenolphthalein and the In- species is the "base color" or pink for this particular indicator, what color will appear in a flask in which a 0.2993 gram sample of KHP has been totaled neutralized with an excess of NaOH?
1.
the flask is pink
2.
the flask is colorless
3.
there is insufficient information to solve this problem
4.
the flask is white from KCl precipitation

What is the value of Kb for the formate anion, HCOO¯? Ka(HCOOH) = 2.1 × 10¯4
a.
2.1 × 10¯4
b.
-2.1 × 10¯4
c.
6.9 × 10¯6
d.
4.8 × 10¯11
e.
2.1 × 10¯18

Use the following information to calculate the solubility product constant, Ksp, for CuCl. A saturated solution of CuCl in water was prepared and filtered. From the filtrate, 1.0 L was measured out into a beaker and evaporated to dryness. The solid CuCl residue recovered in the beaker was found to weigh 0.041g.
a.
Ksp =1.7 × 10¯9
b.
Ksp = 1.7 × 10¯7
c.
Ksp = 1.7 × 10¯5
d.
Ksp = 4.3 × 10¯4
e.
Ksp = 2.1 × 10¯2

Assuming that the total volume does not change after 0.200 g of KCl is added to 1.0 L of a saturated aqueous solution of AgCl, calculate the number of moles of Ag+ ion in the solution after equilibrium has been reestablished. For AgCl, Ksp = 1.8 × 10¯10
a.
1.8 × 10¯10 mol Ag+
b.
9.0 × 10¯10 mol Ag+
c.
9.0 × 10¯9 mol Ag+
d.
6.7 × 10¯8 mol Ag+
e.
1.3 × 10¯5 mol Ag+


Which is not correct concerning equilibrium?
a.
The concentration of reactants and products are no longer changing.
b.
Either the reactants or the products of a reaction could be used to attain equilibrium for a reversible reaction.
c.
The ratio of the concentrations of products and reactants, raised to appropriate powers, is a constant.
d.
The rates of the forward and reverse reactions are the same.
e.
At equilibrium, the rates of the forward and reverse reaction become zero.

The acid dissociation constant Ka equals 1.26 × 10¯2 for HSO4¯ and is 5.6 × 10¯10 for NH4+. Which statement about the following equilibrium is correct?
HSO4¯(aq) + NH3(aq)  ó SO42¯(aq) + NH4+(aq)
a.
This reaction is impossible to predict, since the strong acid and the weak base appear on the same side of the equation.
b.
Neither reactants nor products will be favored because all of the species are weak acids or bases.
c.
The products will be favored because the hydrogen sulfate ion is a stronger acid than the ammonium ion.
d.
The reactants will be favored because ammonia is a stronger base than the sulfate anion.
e.
The initial concentrations of the hydrogen sulfate ion and ammonia must be known before any prediction can be made.

Predict the effect of adding some HCN on the reaction,
CH4(g) + NH3(g) ó HCN + 3 H2(g)
a.
Amount of CH4(g) will increase
b.
Amount of NH3(g) will decrease
c.
Amount of H2(g) will increase
d.
Amount of CH4(g) will stay the same


For the following reaction, which of these changes would produce less CaCO3?
CO2(g) + Ca(OH)2(s) ó CaCO3(s) + H2O(l) DH = -113 kJ
a.
Decrease temperature at constant pressure
b.
Increase volume at constant temperature
c.
Increase the partial pressure of CO2
d.
Remove half of the initial amount of CaCO3
e.
Nothing - as it's a solid, CaCO3 is not involved in the reaction

At a certain temperature, the equilibrium mixture of the reaction PCl5 (g) ⇔ PCl3 + Cl2 (g) has PCl5 = 1.50 atm. PCl3 = 0.10 atm and PCl2 = 7.50 atm Calculate the value of Kp at this temperature.
a.
0.77
b.
2.0
c.
1.0
d.
1.3
e.
0.50

If 1.00 mole of PCl3 and 1.00 mole of Cl2 are placed in a 5.00-L container, the following equilibrium is reached.
PCl3 (g) + Cl2 (g) ⇔ PCl5 (g) Kc = 10.0 at the temperature maintained.
What is the equilibrium concentration of [PCl3] in mol/L?
a.
0.12
b.
0.13
c.
0.14
d.
0.11
e.
0.10

The solubility of silver chromate is 0.0287 g/1.0 L of solution. What is the Ksp for Ag2CrO4?
a.
9.5 × 10¯5
b.
2.6 × 10¯12
c.
6.5 × 10¯13
d.
< 1.0 × 10¯13
e.
2.4 × 10¯5

A 1.25 M solution of the weak acid HA is 9.2% dissociated. What is the pH of the solution?
a.
0.64
b.
0.94
c.
1.13
d.
2.16
e.
None of these choices is correct.




Predict the effect of increasing the container volume on the reaction,
CH4(g) + NH3(g) ó HCN + 3 H2(g)
a.
Amount of CH4(g) will increase
b.
Amount of NH3(g) will decrease
c.
Amount of H2(g) will decrease
d.
Amount of CH4(g) will stay the same
Hydrogen is produced industrially by reacting propane and liquid water:

C3H8(g) + 3 H2O(l) --> 3 CO(g) + 7 H2(g)

If the numerator of the equilibrium expression is expressed as: [CO]m[H2]n, what are the values of "m" and "n"?
1.
2, 1
2.
1, 2
3.
7, 3
4.
3, 7

A 0.050 M solution of the weak acid HA has [H3O+] = 3.77 × 10¯4 M. What is the Ka for the acid?
a.
7.5 × 10¯3 M
b.
2.8 × 10¯6 M
c.
7.0 × 10¯7 M
d.
7.0 × 10¯8 M
e.
2.6 × 10¯11 M

A saturated solution of calcium hydroxide, Ca(OH)2, is in contact with excess solid Ca(OH)2. Which of the following statements correctly describes what will happen when aqueous HCl (a strong acid) is added to this mixture, and system returns to equilibrium? (For Ca(OH)2, Ksp = 6.5 × 10¯6)
a.
The solubility of Ca(OH)2 will be unchanged.
b.
The OH¯ concentration will decrease and the Ca2+ concentration will increase.
c.
The OH¯ concentration will increase and the Ca2+ concentration will decrease.
d.
The concentrations of both Ca2+ and OH¯ will increase.
e.
The solubility of Ca(OH)2 will decrease.



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