Transcript Review for Benchmark #2 - Ms. Lisa Cole--BHS Science

Indicate the equilibrium expressions for the
following reaction: 3Y2(g) + X2(g) <-> 2XY3(g)
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1. [XY3]2 / [X2][Y2]3
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2. [XY3]/[X2][Y2]
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3. 2[XY3]/[X2]3[Y2]
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4. [X2][Y2]3/[XY3]2
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5. [X2][Y2]/[XY3]
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If the formation of ammonia, shown below, is exothermic at 25oC,
what will be the effect of increasing the temperature of the
system? 3H2(g) + N2(g) <-> 2 NH3(g)
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1. The equilibrium will shift to the right
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2. The value of K will increase
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3. The [H2] will decrease
4. The value of K will decrease
5. Equilibrium is dependent on the initial
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concentrations and equation
stoichiometry, not on temperature. There
will be no change
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The image shows a titration of a:
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1. Strong acid with a strong base
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2. Strong acid with a weak base
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3. Weak acid with a strong acid
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4. Weak acid with a strong base
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5. Weak base with a strong acid
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Catalysts lower the activation
energy by:
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1. Providing an alternative pathway for the
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reaction
Increasing the energy content of the
reactants
Changing the value of ΔH for the reaction
Adding heat to the reaction system
None of these
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3.
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The rate law for a reaction is determined to be
rate = k[A]2[B]2. What is the overall order for the reaction?
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1. Zero
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2. Third
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3. Second
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4. First
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5. Fourth
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KClO3 decomposes according to the following reaction:
2KClO3  2KCl + 3O2. If the rate of decomposition of KClO3 at a
certain time is determined to be 2.4 x 10-2 mol s-1, what is the rate
of formation of O2 at the same time?
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1. 1.6 x 10-2 mol/s
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2. 2.4 x 10-2 mol/s
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3. 3.6 x 10-2 mol/s
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4. 1.2 x 10-2 mol/s
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5. 7.2 x 10-2 mol/s
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For the reaction between X and Y the data shown on the table was
obtained. What is the rate law for the reaction?
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1. Rate = k[Y]2
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2. Rate = k[X][Y]
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3. Rate = k[X]2[Y]
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4. Rate = k[X][Y]2
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5. Rate = k[X]2[Y]2
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A certain first order reaction is 50% complete in 4.26 minutes.
What is the rate constant for the reaction?
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1. 0.163 min-1
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2. 0.0252 min-1
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3. 6.13 min-1
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4. 2.95 min-1
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5. [A]o/2t1/2
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For the following reaction, A  B + C that is second order, a linear
plot will result when time is plotted against:
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1. ln[B]
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2. ln[A]
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3. ln[B][C]
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4. 1/[A]
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5. [A]
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Which of the following statements is true for the catalyzed and
uncatalyzed versions of the same reaction?
1. The activation energies are the same10
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2. The energy content of the activated
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complex is higher for the catalyzed
reaction
3. The reaction pathway is the same
4. The energy content of the reactants is
higher for the uncatalyzed reaction
5. ΔHis the same
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The activation energy for the reaction: X2(g) + Y2(g)  2XY(g) is
125 kJ/mol and ΔH for the reaction is -45 kJ/mol. The activation
energy for the decomposition of XY is:
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1. 80 kJ/mol
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2. 170 kJ/mol
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3. 45 kJ/mol
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4. -80 kJ/mol
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5. -125 kJ/mol
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Increasing the temperature at which a reaction occurs speeds up
the reaction by:
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1. Activating catalysts
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2. Two of these
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3. Increasing the energy of collisions
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4. Improving the orientation of collisions
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5. Increasing the frequency of collisions
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For a first order reaction with a rate constant k = 1.2 x 10-3 s-1, how
long will it take for the amount of reactant to be decreased from
0.10 mol to 0.05 mol?
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1. 6.7 s
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2. 580 s
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3. 8.3 x102 s
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4. 8.3 x 103 s
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5. None of these
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A certain first order decomposition reaction reaches 65%
completion in 18.9 s. What is the rate constant for this reaction?
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1. 18 s-1
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2. 5.55 x 10-2 s-1
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3. 2.38 x10-2 s-1
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4. 9.56 x 10-2 s-1
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5. 19.8 s-1
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Consider the following equilibrium:
X2(g) + Y2(g) <-> 2XY(g) + energy
Addition of XY(g) will:
1. Cause [X2] to increase
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2. Drive the reaction to the right
3. Cause the energy of the system to increase
4. Cause [Y2] to decrease
5. Two of these to occur
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The hydrogen halides are all polar molecules
which form acidic solutions. Which of the
following is the weakest acid?
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1. HF
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2. HCl
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3. HBr
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4. HI
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A chemist desires to create a buffer solution beginning with 1.00
liter of 0.200 M NH3. How many moles of gaseous HCl must be
introduced in order to produce a buffer of maximum capacity?
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1. 0.200 mol HCl
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2. 0.100 mol HCl
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3. 0.500 mol HCl
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4. 0.300 mol HCl
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5. None- the solution is already buffered
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The Ksp of BaSO4 is 1.5 x 10-9. How many grams of
BaSO4 can be dissolved in 1000 liters of solution?
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1. 0.085 g
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2. 170 g
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3. 9.1 g
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4. 2.3 g
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5. 39 g
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Calculate the pH of a 0.00175 M
solution of KOH.
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1. -2.76
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2. 7.89
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3. 2.76
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4. 11.2
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5. 12.7
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Imagine a 1.0 L container in 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?
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1. Far to the right
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2. Slightly to the right
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3. Far to the left
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4. Slightly to the left
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5. The reaction is at equilibrium
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Imagine a 1.0 L 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?
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1. 2.02 M
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2. 1.3 M
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3. 2.7 M
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4. 0.7 M
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5. None of these
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For the reaction forming ammonia, 3H2(g) + N2(g) <->2NH3(g),
what effect will increasing the pressure by decreasing the
volume of the system have on this system at equilibrium?
1. It will favor the formation of more
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ammonia
It will shift the equilibrium to the left
The [H2] will increase
The [N2] will increase
It will have no effect on the equilibrium
concentrations.
2.
0%
3.
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4.
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Calculate Ksp of Ba(OH)2 given the fact that the solubility
of Ba(OH)2 in water is 4.6 g per 0.250 liter.
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1. 4.9 x 10-3
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2. 1.2 x 10-2
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3. 1.1 x 10-1
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4. 1.5 x 10-4
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5. 2.0 x 10-7
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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 L. (Ka for propanoic acid =
1.3 x 10-5. What is the pH of the solution when 0.60 mol of NaOH (s) is added
to the solution? Assume no change in solution volume.
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1. 3.97
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2. 4.97
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3. 4.77
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4. 4.67
0%
5. 4.91
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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?
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1. 1.45
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2. 0.76
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3. 0.93
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4. 1.03
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5. 0.82
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You are given a box containing NH3, H2, and N2 at equilibrium at
1000oC. Analysis of the contents shows the concentrations as follow:
[NH3] = 0.102 M, [H2] = 1.62 M, and [N2] = 1.03 M. Calculate K for the
reaction: 2NH3(g) <-> N2(g) + 3H2(g)
0%
1. 2.37 x 10-3
0%
2. 4.21 x 102
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3. 3.89 x 10-4
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4. 3.89 x 104
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5. 9.02 x 10-6
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Imagine a 1.0 L 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
temperature of the system would:
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1. Drive the reaction to the right
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2. Drive the reaction to the left
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3. Have no effect on the reaction
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4. The effect cannot be determined
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Which of the following is always true for a reaction
whose value for K is 4.4 x 104?
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1. The reaction proceeds far to the right
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2. The reaction proceeds far to the left
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3. The reaction occurs quickly
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4. The reaction occurs slowly
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5. Two of these
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If an acid, HA, is 15% dissociated in a 2.00 M solution,
what is the Ka for the acid?
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1. 7.5 x 10-2
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2. 1.2 x 10-2
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3. 1.1 x 10-2
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4. 5.3 x 10-2
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5. 6.4 x 10-3
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Suppose that 0.250 L of a buffer solution contains 0.225 M acetic acid
and 0.225 M soldium acetate. What would be the pH change if 30.0 mL
of 0.100 M HCl is added to this buffer? Assume the volumes are
additive. Ka for acetic acid is 1.8 x 10-5.
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1. 4.70 to 4.78
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2. 4.74 to 4.70
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3. 4.74 to 4.82
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4. 5.40 to 7.68
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5. 6.40 to 4.56
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At 25oC a solution has a [OH-] = 2.90 x 10-2.
Calculate the pH of the solution.
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1. 12.5
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2. 1.54
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3. -4.54
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4. 9.03
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5. 3.17
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What is the pH of a buffer solution consisting of 0.150 mol of NH3
plus 0.250 mol of NH4Cl in enough water to make 0.750 liter of
solution? Kb = 1.81.x 10-5.
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1. 9.038
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2. 4.963
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3. 2.721
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4. 11.279
0%
5. 8.547
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50.0 mL of 0.100 M NH3 Is titrated with 0.025 M HCl. What is the
pH of the solution after 100 mL of HCl has been added?
Kb for NH3 = 1.81 x 10-5
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1. 4.74
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2. 12.45
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3. 10.90
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4. 8.99
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5. 9.26
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What is the pH of a 0.00350 M HNO3 solution?
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1. -2.46
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2. 2.46
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3. 1.01
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4. 6.78
0%
5. 4.90
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What is the correct unit for the rate constant for
a reaction that is first order overall?
0%
1. L/mol s
0%
2. Mol/L s
0%
3. Mol2/L2 s
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4. L2/Mol2 s
0%
5. s-1
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The most common types of radioactive decay, in order
from most penetrating to least penetrating, is
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1. alpha, beta, gamma
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2. beta, gamma, alpha
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3. gamma, alpha, beta
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4. gamma, beta, alpha
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Phophorus-15 has a half life of 14 days. What fraction of
the original phosphorus-15 remains after 8 weeks?
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1. ¼
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2. 1/8
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3. 1/32
0%
4. ½
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5. 1/16
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What isotope forms as potassium-37 undergoes
positron emission?
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1. Argon-37
0%
2. Argon-38
0%
3. Argon-36
0%
4. Calcium-37
0%
5. Calcium-38
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Which of the following statements is true?
1. All man-made isotopes are radioactive.
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2. Some man-made isotopes are radioactive
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3. None of the man-made isotopes are
radioactive.
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The nuclide radium-226 is the daughter nuclide resulting
from the alpha decay of what parent nuclide?
0%
1. Radium-225
0%
2. Polonium-214
0%
3. Thorium-230
0%
4. Radon-222
0%
5. Thorium-228
10
1
2
3
4
5
6
7
8
9
10
11
12
21
22
23
24
25
26
27
28
29
30
31
32
13
14
15
16
17
18
19
20
An electron emitted from the nucleus during some kinds of
radioactive decay is known as
0%
1. A beta particle
0%
2. An alpha particle
0%
3. A gamma ray
0%
4. A positron
10
1
2
3
4
5
6
7
8
9
10
11
12
21
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31
32
13
14
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19
20
Carbon-12 and carbon-13 are stable isotopes of the
element. Which of the following isotopes is most likely
to undergo positron emission?
0%
1. Carbon-11
0%
2. Carbon-14
0%
3. Carbon-12
0%
4. Carbon-13
0%
5. Carbon-15
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1
2
3
4
5
6
7
8
9
10
11
12
21
22
23
24
25
26
27
28
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30
31
32
13
14
15
16
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18
19
20