Multiple-choice exercise. Twenty questions will be loaded at random each time you attempt this review activity.
Choose the correct answer for each question.
Indicate the mass expression for the following reaction:
3Y_{2}(g) + X_{2}(g) ↔ 2XY_{3}
Determine the equilibrium constant for the system 2XY_{3} ↔ 2X + 3Y_{2} at 25°C. The concentrations are shown here: [XY_{3}] = 1.23 x 10^{-2} M, [X] = 2.50 x 10^{-2} M, [Y_{2}] = 3.75 x 10^{-2} M
2.68 x 10^{-4}
3.30 x 10^{-8}
7.19 x 10^{-3}
9.81 x 10^{-6}
None of these
One mole of gaseous HA is placed in a one liter container. At equilibrium it is 18% dissociated according to the equation shown here:
2HA ↔ 2H + A_{2}
Determine the equilibrium constant.
K = 0.82
K = 0.0071
K = 0.0043
K = 0.0094
K = 0.0012
You are given a box containing NH_{3}, N_{2}, and H_{2} at equilibrium at 1000°C. Analysis of the contents shows that the concentration of NH_{3} is 0.102 mole/liter, N_{2} is 1.03 moles/liter, and H_{2} is 1.62 moles/liter. Calculate K for the reaction: 2NH_{3}(g) ↔ N_{2}(g) + 3H_{2}(g)
2.37 x 10^{-3}
4.21 x 10^{2}
3.89 x 10^{-4}
3.89 x 10^{4}
9.02 x 10^{-6}
Consider the following equilibrium:
X_{2}(g) + Y_{2}(g) ↔ 2XY(g) + energy
Addition of XY(g) will:
Cause [X_{2}] to increase
Drive the reaction toward the right
Cause the energy of the system to increase
Cause [Y_{2}] to decrease
Two of these occur
Consider the following equilibrium:
X_{2}(g) + Y_{2}(g) ↔ 2XY(g) + energy
Heating the system will:
Cause [X_{2}] to decrease
Drive the reaction toward the right
Cause [Y_{2}] to decrease
Cause [XY] to decrease
Two of these occur
Which of the following is always true for a reaction whose value for K is 4.4 x 10^{4}?
The reaction proceeds far to the right
The reaction proceeds far to the left
The reaction occurs quickly
The reaction occurs slowly
Two of these
Imagine a one liter container into which 2.0 mol samples of gaseous substances A, B, and C are introduced. A and B react according to the following equation:
A(g) + B(g) ↔ 2C(g)
If the value of K = 4.2, in what direction does the equilibrium exist?
Far to the right
Slightly to the right
Far to the left
Slightly to the left
The reaction is at equilibrium
Imagine a one liter container into which 2.0 mol samples of gaseous substances A, B, and C are introduced. A and B react according to the following equation:
A(g) + B(g) ↔ 2C(g)
If K = 2.68 for this reaction, what is the equilibrium concentration of C?
2.02 M
1.3 M
2.7 M
0.7 M
None of these
Imagine a one liter container into which 2.0 mol samples of gaseous substances A, B, and C are introduced. A and B react according to the following equation:
A(g) + B(g) ↔ 2C(g)
An increase in the temperature of the system would:
Drive the reaction to the right
Drive the reaction to the left
Have no effect on the reaction
The effect cannot be determined
For the reaction forming ammonia,
3H_{2}(g) + N_{2}(g) ↔ 2NH_{3}(g)
What effect will increasing the pressure by decreasing the volume of the system have on this system at equilibrium?
It will favor the formation of more ammonia
It will shift the equilibrium to the left
The [H_{2}] will increase
The [N_{2}] will increase
It will have no effect on the equilibrium concentrations
If the formation of ammonia, shown below, is exothermic at 25°C, what will be the effect of increasing the temperature of the system?
3H_{2}(g) + N_{2}(g) ↔ 2NH_{3}(g)
The equilibrium will shift to the right
The value of K will increase
The [H_{2}] will decrease
The value of K will decrease
Equilibrium is dependent on initial concentrations and equation stoichiometry, not on temperature. There will be no change.
Identify the strong acid:
HF
HCO_{3}^{-}
HClO_{4}
H_{2}O
HCN
Which of the following is not true for the dissociation of a strong acid?
K_{a} is large
The equilibrium lies far to the left
The equilibrium lies far to the right
[H^{+}] >> [HA]
The conjugate base will be weak
What is the pH of a 0.00350 M HNO_{3} solution?
-2.46
2.46
1.01
6.78
4.90
Calculate the [H^{+}] in a solution that has a pH of 8.38.
1.21 x 10^{2}
1.21 x 10^{-2}
3.8 x 10^{-8}
2.40 x 10^{8}
4.17 x 10^{-9}
At 25°C a solution has a [OH^{-}] = 2.90 x 10^{-2}. Calculate the pH of the solution.
12.5
1.54
-4.54
9.03
3.17
What are the conjugate bases in the following reaction?
H_{2}SO_{4} + H_{2}O → HSO_{4}^{-} + H_{3}O^{+}
H_{2}SO_{4} and H_{2}O
H_{2}SO_{4} and H_{3}O^{+}
H_{2}O and HSO_{4}^{-}
HSO_{4}^{-} and H_{3}O^{+}
H_{2}SO_{4}, H_{2}O and HSO_{4}^{-}
Based upon the following values of K_{a}, place the acids in order from weakest to strongest:
HCN (K_{a} = 6.2 x 10^{-10})
HCOOH (K_{a} = 1.78 x 10^{-4})
HC_{2}H_{3}O_{2} (K_{a} = 1.8 x 10^{-5})
HNO_{2} (K_{a} = 4.6 x 10^{-4})
HC_{2}H_{3}O_{2} < HCN → HNO_{2} < HCOOH
HNO_{2} < HCOOH < HC_{2}H_{3}O_{2} < HCN
HCN < HNO_{2} < HC_{2}H_{3}O_{2} < HCOOH
HCOOH < HNO_{2} < HCN < HC_{2}H_{3}O_{2}
HCN < HC_{2}H_{3}O_{2} < HCOOH < HNO_{2}
The hydrogen halides are all polar molecules which form acidic solutions. Which of the following is the weakest acid?
HF
HCl
HBr
HI
The pH of a 0.500 M solution of KC_{2}H_{3}O_{2} is:
greater than 7
less than 7
7
Calculate the pH of a 0.00175 M solution of KOH.
-2.76
7.89
2.76
11.2
12.7
The pH of a 0.150 M solution of an aqueous weak monoprotic acid is 4.10. Calculate K_{a} for the acid.
4.21 x 10^{-8}
7.94 x 10^{-5}
6.31 x 10^{-9}
2.26 x 10^{-4}
5.09 x 10^{-2}
If an acid, HA, is 15% dissociated in a 2.00 M solution, what is K_{a} for the acid?
7.5 x 10^{-2}
1.2 x 10^{-2}
1.1 x 10^{-2}
5.3 x 10^{-2}
6.4 10^{-3}
What concentration of HOCl (K_{a} = 3.5 x 10^{-8}) has the same pH as that of 2.50 x 10^{-4} M HNO_{3}?
1.79 M
0.560
3.5 x 10^{-2} M
6.8 10^{-8} M
3.93 M
Calculate the [H_{3}O^{+}] of a 0.10 M solution of NH_{4}Cl in H_{2}O at 25°C (K_{b} for NH_{3} = 1.8 x 10^{-5})
2.4 x 10^{-5}
5.6 x 10^{-10}
1.8 x 10^{-5}
7.5 x 10^{-6}
1.8 x 10^{-6}
Calculate the pH of a 0.0075 M solution of potasium oxide, K_{2}O.
-1.8
1.8
12.2
11.9
2.1
Which of the following pairs of compounds could create a suitable buffer system?
sodium chloride and sodium hydroxide
sodium sulfate and sodium hydroxide
sodium acetate and acetic acid
carbonic acid and sodium chloride
ammonia and potassium hydroxide
What is the pH of a solution that is 0.50 M in propanoic acid and 0.40 M in sodium propanoate. (K_{a} for propanoic acid = 1.3 x 10^{-5})
0.097
4.98
0.47
4.79
-4.98
A buffer solution is prepared that is 0.50 M in propanoic acid and 0.40 M in sodium propanoate with a solution volume of 1.00 liters. (K_{a} for propanoic acid = 1.3 x 10^{-5}). What is the pH of the solution when 0.040 mol of HCl(g) is added to the solution? Assume no change in solution volume.
4.71
4.87
5.06
4.91
4.78
A buffer solution is prepared that is 0.50 M in propanoic acid and 0.40 M in sodium propanoate with a solution volume of 1.00 liters. (K_{a} for propanoic acid = 1.3 x 10^{-5}). What is the pH of the solution when 0.060 mol of NaOH(s) is added to the solution? Assume no change in solution volume.
3.97
4.97
4.77
4.67
4.91
Suppose that 0.250 liters of a buffer solution that contains 0.225 M acetic acid and 0.225 M sodium acetate. What would be the pH change if 30.0 mL of 0.100 M HCl is added to this buffer? Assume volumes are additive. K_{a} for acetic acid is 1.8 x 10 ^{-5}.
4.70 to 4.78
4.74 to 4.70
4.74 to 4.82
5.40 to 7.68
6.40 to 4.56
What is the pH of a buffer solution consisting of 0.150 mol of NH_{3} plus 0.250 mol of NH_{4}Cl in enough water to make 0.750 liter of solution. K_{b} = 1.81 x 10^{-5}.
9.038
4.963
2.721
11.279
8.547
80.0 mL of a buffer solution contains 0.169 M NH_{3} and 0.183 M NH_{4}Cl. If you add 10.0 mL of 0.100 M HCl, what will be the pH? K_{b} = 1.81 x 10^{-5}. Assume additive volumes.
9.223
8.985
10.309
9.161
7.908
K_{a} for HNO_{2} is 4.5 x 10^{-4}, calculate the pH of a buffer solution made by mixing 0.225 mol of HNO_{2} and 0.450 mol of NaNO_{2} in enough water to make 0.400 liter of solution.
3.51
2.98
3.90
5.72
3.65
Suppose you are given 0.50 liter of 0.500 M acetic acid, and 0.50 liter of 0.250 liter sodium acetate. What is the maximum volume of buffer solution that you can make if the buffer must have a pH of 4.58? K_{a} for acetic acid is 1.8 x 10^{-5}.
0.50 liter
0.86 liter
0.287 liter
0.91 liter
0.78 liter
A chemist desires to create a buffer solution beginning with 1.00 liter of 0.200 M NH_{3}. How many moles of gaseous HCl must be introduced in order to produce a buffer of maximum capacity. Assume no increase in solution volume.
0.200 mol HCl
0.100 mol HCl
0.500 mol HCl
0.300 mol HCl
None - the solution is already buffered
The K_{sp} of BaSO_{4} is 1.5 x 10^{-9}. What is the molar concentration of Ba^{2+}(aq) in a saturated solution of BaSO_{4}?
2.25 x 10^{-18} M
3.9 x 10^{-5} M
1.7 x 10^{-2} M
2.45 x 10^{-5} M
6.7 x 10^{-15} M
The K_{sp} of BaSO_{4} is 1.5 x 10^{-9}. How many grams of BaSO_{4} can be dissolved in 1000. liters of solution?
0.085 g
170 g
9.1 g
2.3 g
39 g
Calculate the K_{sp} of Ba(OH)_{2} given the fact that the solubility of Ba(OH)_{2} in water is 4.6 g per 0.250 liter.
4.9 x 10^{-3}
1.2 x 10^{-2}
1.1 x 10^{-1}
1.5 x 10^{-4}
2.0 x 10^{-7}
The image above shows the titration of a:
strong acid with a strong base
Strong acid with a weak base
Weak acid with a strong acid
Weak acid with a strong base
weak base with a strong base
200.0 mL of 0.200 M HCl is titrated with 0.050 M NaOH. What is the pH after the addition of 100. mL of the NaOH solution?
1.45
0.76
0.93
1.03
0.82
50.0 mL of 0.100 M NH_{3} is titrated with 0.025 M HCl. What is the pH of the solution after 100.0 mL of HCl has been added? K_{b} for NH_{3} 1.81 x 10^{-5}.