Reactions and Equilibrium - AP Chemistry
Card 1 of 2660
Put the following in order of INCREASING acid strength: H2Se, KH, AsH3, HBr.
Put the following in order of INCREASING acid strength: H2Se, KH, AsH3, HBr.
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Acid strength increases going across a period.
Acid strength increases going across a period.
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What is the pH of a solution that has \[OH-\] 1 X 10–4 M?
What is the pH of a solution that has \[OH-\] 1 X 10–4 M?
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pOH would be 4 (use –log \[OH–\]) and pH would be 14–pOH = 14 – 4 = 10
pOH would be 4 (use –log \[OH–\]) and pH would be 14–pOH = 14 – 4 = 10
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What is the pH of a solution with \[OH-\] = 4 X 10-6
What is the pH of a solution with \[OH-\] = 4 X 10-6
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\[OH-\] = 4 X 10-6
pOH = 5.4 — use –log \[OH–\] to find pOH
pH = 14– pOH = 8.6
\[OH-\] = 4 X 10-6
pOH = 5.4 — use –log \[OH–\] to find pOH
pH = 14– pOH = 8.6
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Which of the following will produce the solution with the lowest pH?
Which of the following will produce the solution with the lowest pH?
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NaOH is a base, so that won't produce an acidic solution. Of the remaining acids, HCl and HI are strong acids, and HF is weak. HI is at a higher molarity, so it will produce the most acidic solution.
NaOH is a base, so that won't produce an acidic solution. Of the remaining acids, HCl and HI are strong acids, and HF is weak. HI is at a higher molarity, so it will produce the most acidic solution.
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In the following equation, which is the conjugate base of HClO4?
HClO4 + H2O → ClO4– + H3O+
In the following equation, which is the conjugate base of HClO4?
HClO4 + H2O → ClO4– + H3O+
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The conjugate base of an acid will be the same compound, short one H atom. ClO4– is the only one that meets this criterion.
The conjugate base of an acid will be the same compound, short one H atom. ClO4– is the only one that meets this criterion.
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Which of the following is a Lewis base?
Which of the following is a Lewis base?
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A Lewis base is an electron-pair donor. Only PH3 has a pair of nonbonding electrons and can act as a donor.
A Lewis base is an electron-pair donor. Only PH3 has a pair of nonbonding electrons and can act as a donor.
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Which of the following is the conjugate base of oxalic acid (H2C2O4)?
Which of the following is the conjugate base of oxalic acid (H2C2O4)?
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The conjugate base has one less H atoms and one unit greater negative charge because of this. Thus, the correct answer is HC2O4–
The conjugate base has one less H atoms and one unit greater negative charge because of this. Thus, the correct answer is HC2O4–
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Which of the following is a strong acid?
Which of the following is a strong acid?
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This question is simply testing your memorization of strong and weak acids. Of the list, you should recognize that nitric acid is the only strong acid, and the rest of the choices are weak.
This question is simply testing your memorization of strong and weak acids. Of the list, you should recognize that nitric acid is the only strong acid, and the rest of the choices are weak.
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What is the difference between the reaction quotient and the equilibrium constant?
What is the difference between the reaction quotient and the equilibrium constant?
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The correct answer gives the accurate definition of both the equilibrium constant and the reaction quotient.
The correct answer gives the accurate definition of both the equilibrium constant and the reaction quotient.
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Which of the following can always be determined based on the equation itself?
Which of the following can always be determined based on the equation itself?
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According to the law of mass action, the equilibrium constant expression can always be written given the equation of the reaction itself. The equilibrium-constant expression will be written as the products over the reactants, each raised to their respectively stoichiometric coefficient. The rate law and concentrations can only be determined if there is additional data given.
According to the law of mass action, the equilibrium constant expression can always be written given the equation of the reaction itself. The equilibrium-constant expression will be written as the products over the reactants, each raised to their respectively stoichiometric coefficient. The rate law and concentrations can only be determined if there is additional data given.
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The law of mass action gives an expression that is specific for a certain .
The law of mass action gives an expression that is specific for a certain .
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Equilibrium expressions are specific for certain temperatures. Physical state, pressure, and volume do not factor into the expression.
Equilibrium expressions are specific for certain temperatures. Physical state, pressure, and volume do not factor into the expression.
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Consider formation of Nitrogen monoxide: 
with 
. If the initial concentration of N2 was 0.085M and O2 was 0.038 M, what is the concentration of nitrogen monoxide at equilibrium?
Consider formation of Nitrogen monoxide: 
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Given the ICE table below, what are the signs on the terms that would appear in the “Change” row?
Given the ICE table below, what are the signs on the terms that would appear in the “Change” row?
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Based on the balanced equation, one would use -x, -2x, and +x.
Based on the balanced equation, one would use -x, -2x, and +x.
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Find the equilibrium concentrations for C in the following chemical reaction: A + B -> 2C
K = 9.0 x 10-8
Find the equilibrium concentrations for C in the following chemical reaction: A + B -> 2C
K = 9.0 x 10-8
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What is the equilibrium concentration for A- in the following reaction if the starting concentration of HA is 0.60 M?
What is the equilibrium concentration for A- in the following reaction if the starting concentration of HA is 0.60 M?
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What is the equilibrium concentration for A- in the following reaction if the starting concentration of HA is 0.30 M?
What is the equilibrium concentration for A- in the following reaction if the starting concentration of HA is 0.30 M?
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Consider the following gasesous, reversible, exothermic reaction:
What could be done to increase the equilibrium concentration of species C?
Consider the following gasesous, reversible, exothermic reaction:
What could be done to increase the equilibrium concentration of species C?
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According to Le Chatelier's principle, any changes in concentration or pressure to a system at equilibrium will cause the system to readjust to a new equilbrium. The addition of a reactant will cause the reaction to shift to the right, increasing the equilibirum concentration of the products. Thus, adding additional reactant A would increase the equlibrium concentration of product C.
Removing species A or adding species E will drive the reaction to the left, reducing the amount of species C. Since the reaction is exothermic, heat can be considered a product. Thus, increasing the temperature will also shift the reaction to the left.
According to Le Chatelier's principle, any changes in concentration or pressure to a system at equilibrium will cause the system to readjust to a new equilbrium. The addition of a reactant will cause the reaction to shift to the right, increasing the equilibirum concentration of the products. Thus, adding additional reactant A would increase the equlibrium concentration of product C.
Removing species A or adding species E will drive the reaction to the left, reducing the amount of species C. Since the reaction is exothermic, heat can be considered a product. Thus, increasing the temperature will also shift the reaction to the left.
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The reaction 
is at equilibrium. You have measured the concentration of 
and 
to be
What is the equilibrium constant, 
?
The reaction
What is the equilibrium constant,
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Recall that the rate constant for the equilibrium reaction
is 
, always remembering that it is products over reactants.
Since we are at equilibrium, for every mol of 
we have, we have 3 mols of 
. Therefore,
Likewise, for every 2 mols of 
we have, we have 2 mols of 
. Therefore,
Plugging all of this into the above equation we get
Recall that the rate constant for the equilibrium reaction
is
Since we are at equilibrium, for every mol of
Likewise, for every 2 mols of
Plugging all of this into the above equation we get
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Consider the following chemical reaction.
This reaction is allowed to equilibrate at some volume and pressure.
Which of the following actions will not shift the equilibrium toward the products?
Consider the following chemical reaction.
This reaction is allowed to equilibrate at some volume and pressure.
Which of the following actions will not shift the equilibrium toward the products?
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Adding an inert gas will not shift the equilibrium toward the products, but neither will it shift the equilibrium toward the reactants. It has no effect because the partial pressure of each species, 
, 
, and 
, will still remain constant. Since the partial pressures are constant, we know from the ideal gas law that the concentration of each species remains constant. For example, for 
,
Adding an inert gas will not shift the equilibrium toward the products, but neither will it shift the equilibrium toward the reactants. It has no effect because the partial pressure of each species,
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A reaction at equilibrium releases 25 Joules of heat energy at 
. What is the entropy change for this same reaction?
A reaction at equilibrium releases 25 Joules of heat energy at
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To solve this problem, we must make use of the following equation:
At equilibrium, the value of 
is 0. Therefore, we can simplify the equation.
We must also convert temperature from degress Celsius into Kelvin.
To solve this problem, we must make use of the following equation:
At equilibrium, the value of
We must also convert temperature from degress Celsius into Kelvin.
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