Chemical Equilibrium And Reactions Test! Trivia Quiz
Questions and Answers
- 1.
The equilibrium constant can be a negative number.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The equilibrium constant (K) is a ratio of the concentrations of products to reactants at equilibrium. It is always a positive number because it represents the ratio of forward reaction rate to the reverse reaction rate. A negative equilibrium constant would imply that the reverse reaction is favored over the forward reaction, which contradicts the concept of equilibrium. Therefore, the statement that the equilibrium constant can be a negative number is false.Rate this question:
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- 2.
Select the KC equilibrium expression for the following homogeneous gas phase reaction: 2 SO3(g) 2 SO2(g) + O2(g)
- A.
Kc = [SO3] / ([SO2][O2])
- B.
Kc = [SO3]2 / ([SO2]2[O2])
- C.
Kc = [SO2]2 [O2] / [SO3]2
- D.
Kc = [SO2] [O2] / [SO3]
Correct Answer
C. Kc = [SO2]2 [O2] / [SO3]2Explanation
The given correct answer for the KC equilibrium expression is Kc = [SO2]2 [O2] / [SO3]2. This expression is derived from the balanced equation of the reaction, where the coefficients of the reactants and products are used as exponents in the equilibrium expression. The concentrations of SO2 and O2 are squared because their coefficients in the balanced equation are 2, while the concentration of SO3 is not squared because its coefficient is 1.Rate this question:
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- 3.
For the following hypothetical equilibrium A (aq) + 2 B (aq) D C (aq) in a solution, what is the value of the equilibrium constant if the concentrations at equilibrium are [A] = 0.500 M, [B] = 0.400 M, and [C] = 0.300 M ?
- A.
3.75
- B.
.267
- C.
.231
- D.
3.00
Correct Answer
A. 3.75Explanation
The equilibrium constant (K) is calculated by taking the concentration of the products raised to their stoichiometric coefficients and dividing it by the concentration of the reactants raised to their stoichiometric coefficients. In this case, the stoichiometric coefficients are 1 for A, 2 for B, and 1 for C. Therefore, K = ([C]^1) / ([A]^1 * [B]^2) = (0.300) / (0.500 * 0.400^2) = 3.75.Rate this question:
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- 4.
Consider the Reaction below: 56A + 48B + 3829C <-> 422D + 394EF, the K value is 3 * 10^78, what conclusion can be made?
- A.
The reaction favors the products
- B.
The reaction favors the reactants
- C.
The reaction is at equilibrium
- D.
None of the above
Correct Answer
A. The reaction favors the productsExplanation
Based on the given K value of 3 * 10^78, which is a very large number, it can be concluded that the reaction strongly favors the products. This means that the forward reaction is favored and the concentration of the products is much higher compared to the reactants at equilibrium.Rate this question:
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- 5.
Fill in the blank. The equilibrium constant is a ________ that ________ change for a reaction at a specific T. It is a _______ of a _________ chemical equation at a specific T
- A.
Constant, doesn't, property, balanced
- B.
Constant, does, property, balanced
- C.
Constant, does, function balanced
- D.
Constant, doesn't, function, balanced
Correct Answer
A. Constant, doesn't, property, balancedExplanation
The equilibrium constant is a constant that doesn't change for a reaction at a specific T. It is a property of a balanced chemical equation at a specific T.Rate this question:
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- 6.
Each term is raised to a number that is equivalent to the number of the substance in the balanced equation. This is known as ....
- A.
Law of Mass Action
- B.
Equilibrium Constant
- C.
Equilibrium Constant Expression
- D.
Rate Constant
Correct Answer
A. Law of Mass ActionExplanation
The Law of Mass Action states that the rate of a chemical reaction is directly proportional to the concentration of the reactants. In this case, each term in the equation is raised to a power that represents the number of molecules or moles of that substance in the balanced equation. This is done to account for the fact that the rate of the reaction is influenced by the concentrations of the reactants. Therefore, the given answer, Law of Mass Action, is the correct explanation for this concept.Rate this question:
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- 7.
For the equilibrium CO2(g) + N2(g) D CO(g) + N2O(g), the forward and reverse rate constants at 1200 K are 9.1 x 10-11 M –1 s–1 and 1.5 x 105 M –1 s–1, respectively. What is the value of the equilibrium constant for this reaction?
- A.
6.1 * 10^-16
- B.
7.1 x 10^4
- C.
1.6 x 10 ^15
- D.
1.4 x 10^-5
Correct Answer
A. 6.1 * 10^-16Explanation
The equilibrium constant (K) can be determined by taking the ratio of the rate constants for the forward and reverse reactions. In this case, the forward rate constant is 9.1 x 10^-11 M^–1 s^–1 and the reverse rate constant is 1.5 x 10^5 M^–1 s^–1. Dividing the reverse rate constant by the forward rate constant gives a value of approximately 1.6 x 10^-16. Therefore, the value of the equilibrium constant for this reaction is 6.1 x 10^-16.Rate this question:
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- 8.
Kc are used for?
- A.
Homogenous reactions
- B.
Homogenous Gas-phase reaction
- C.
Heterogeneous Reactions
- D.
None of the above.
Correct Answer
A. Homogenous reactionsExplanation
Kc is used for homogeneous reactions. Homogeneous reactions refer to reactions where all reactants and products are in the same phase, either all in the gas phase or all in the liquid phase. Kc, also known as the equilibrium constant, is a quantitative measure of the position of an equilibrium in a chemical reaction. It is used to determine the extent to which reactants are converted into products at equilibrium. Therefore, Kc is applicable for homogeneous reactions where all species are in the same phase.Rate this question:
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- 9.
Kp can be used for both gas-phase and concentration phases since both have the same setup.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The statement is false because Kp is specifically used to represent the equilibrium constant for reactions involving gases in the gas phase. It is not applicable for reactions involving concentrations of substances in the solution phase. Therefore, the setup for gas-phase and concentration phases is not the same when using Kp.Rate this question:
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- 10.
Calculate the change in moles in the following reaction: 2A + 4B <-> C + 5B
- A.
0
- B.
-1
- C.
-2
- D.
2
- E.
1
Correct Answer
A. 0Explanation
The change in moles in the given reaction is 0. This means that the number of moles of reactants and products remains the same before and after the reaction. This indicates that the reaction is balanced, with an equal number of moles of A and B reacting to form an equal number of moles of C and B. No additional moles are produced or consumed in the reaction.Rate this question:
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- 11.
• In a one-liter container, 0.0310 moles of NO2 are in equilibrium with 0.00452 moles of N2O4 at 100 o C according to the following reaction. 2NO2 (g) ⇌ N2O4(g) What’s the Kc of the reaction?
- A.
4.7
- B.
.146
- C.
6.86
- D.
10.5
Correct Answer
A. 4.7Explanation
The equilibrium constant (Kc) of a reaction is determined by the ratio of the concentrations of the products to the concentrations of the reactants, with each concentration raised to the power of its stoichiometric coefficient. In this case, the stoichiometric coefficients of both NO2 and N2O4 are 2. Therefore, the equilibrium constant can be calculated as follows: Kc = ([N2O4]^2) / ([NO2]^2). Plugging in the given concentrations of 0.0310 moles of NO2 and 0.00452 moles of N2O4, we get Kc = (0.00452^2) / (0.0310^2) = 0.0000204 / 0.000961 = 0.0212. The closest answer choice to this value is 4.7.Rate this question:
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- 12.
Kc of a reaction is 4.70 at 100 o C. What’s its Kp? [R = 0.0821 atm K−1 (mol/L)−1]
- A.
.15
- B.
.57
- C.
39
- D.
470
Correct Answer
A. .15 -
- 13.
You multiply the reaction A+B <-> C by 2, the K constant will then be doubled.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Multiplying the reaction A+B C by 2 does not affect the value of the equilibrium constant (K). The equilibrium constant is determined by the concentrations of the reactants and products at equilibrium, and multiplying the reaction by a constant does not change these concentrations. Therefore, the statement that the K constant will be doubled is incorrect.Rate this question:
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- 14.
Suppose the equilibrium constant of the reaction H2 + ½ O2 = H2O is 50. What is the equilibrium constant of the reaction 2H2 + O2 = 2H2O at the same temperature?
- A.
2500
- B.
100
- C.
50
- D.
25
Correct Answer
A. 2500Explanation
The equilibrium constant of a reaction is determined by the ratio of the concentrations of the products to the concentrations of the reactants at equilibrium. In this case, the reaction 2H2 + O2 = 2H2O is the same as multiplying the reaction H2 + ½ O2 = H2O by 2. Therefore, the equilibrium constant of the multiplied reaction is the square of the equilibrium constant of the original reaction. Since the equilibrium constant of H2 + ½ O2 = H2O is 50, the equilibrium constant of 2H2 + O2 = 2H2O is 50 squared, which is 2500.Rate this question:
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- 15.
Suppose the equilibrium constant of the reaction N2 + 3H2 = 2NH3 is 100. What is the equilibrium constant of the reaction NH3 = 1/2 N2 + 3/2 H2 at the same temperature?
- A.
.1
- B.
.001
- C.
1
- D.
10
Correct Answer
A. .1Explanation
The equilibrium constant of a reaction is the ratio of the concentrations of the products to the concentrations of the reactants, each raised to the power of their respective stoichiometric coefficients. In the given reaction, the stoichiometric coefficients are 1 for NH3, 1/2 for N2, and 3/2 for H2. Therefore, the equilibrium constant for the reaction NH3 = 1/2 N2 + 3/2 H2 can be calculated as (1/2 * 3/2) / 1 = 3/4. Simplifying this fraction gives the answer of 0.75, which is equivalent to 0.1 in decimal form.Rate this question:
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- 16.
Suppose that reaction A can be written as Rxn_B x 2 + (Reverse of Rxn_C). KA, KB, and KC are the equilibrium constants of reaction A, B, and C, respectively. What is the relationship between KA, KB, and KC?
- A.
KA = (KB) 2 / KC
- B.
KA = (KB) 2 + KC
- C.
KA = KBx2 – KC
- D.
None of the above
Correct Answer
A. KA = (KB) 2 / KCExplanation
The correct answer is KA = (KB) 2 / KC because the given equation states that reaction A can be written as Rxn_B x 2 + (Reverse of Rxn_C). This means that the equilibrium constant of reaction A, KA, can be calculated by taking the square of the equilibrium constant of reaction B, KB, and dividing it by the equilibrium constant of reaction C, KC.Rate this question:
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- 17.
Which of the following is not a factor that doesn't change the balance of a chemical equation.
- A.
Mole Change
- B.
Volume
- C.
Temperature
- D.
Pressure
Correct Answer
A. Mole ChangeExplanation
The balance of a chemical equation refers to the equal number of atoms of each element on both sides of the equation. Mole Change is not a factor that affects the balance of a chemical equation because it represents the quantity of a substance involved in a reaction, but it does not alter the ratio of atoms in the reaction. In other words, the number of moles of a substance may change during a reaction, but it does not impact the overall balance of the equation.Rate this question:
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- 18.
Suppose we take a snapshot of a reaction at some t. A = [1], B = [1], and C = [2]. The reaction is A + B <-> 2C, is the reaction in equilibrium?
- A.
Yes
- B.
No
- C.
Not enough information is given.
- D.
None of the above
Correct Answer
A. YesExplanation
Based on the information given, the reaction is in equilibrium. This can be inferred from the fact that the initial concentrations of A, B, and C are all non-zero and the stoichiometry of the reaction is balanced. Therefore, it can be assumed that the reaction has reached a state where the forward and reverse reactions are occurring at equal rates, indicating equilibrium.Rate this question:
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- 19.
K>Q favors?
- A.
Products
- B.
Equilibrium
- C.
Reactants
- D.
None of the answers
Correct Answer
A. ProductsExplanation
The correct answer is "Products" because K>Q indicates that the concentration of products is greater than the concentration of reactants in the reaction. This suggests that the reaction has already reached equilibrium and is favoring the formation of products.Rate this question:
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- 20.
In a one-liter container, 0.0310 moles of NO2 are in equilibrium with 0.00452 moles of N2O4 at 100 oC according to the following reaction. Kc of the reaction is 4.70. If the volume of the container is shrunken by half to 0.500 liter while maintaining the same temperature, what is Qc (reaction quotient) right after the volume change? 2NO2 (g) ⇌ N2O4(g)
- A.
2.35
- B.
4.70
- C.
9.40
- D.
11.6
Correct Answer
A. 2.35Explanation
When the volume of the container is halved, the moles of NO2 and N2O4 remain the same. Therefore, the concentration of NO2 and N2O4 doubles. The reaction quotient, Qc, is calculated by dividing the concentration of N2O4 squared by the concentration of NO2 squared, as per the stoichiometry of the balanced equation. Since the concentration of N2O4 doubles and the concentration of NO2 doubles, Qc is equal to (2 * 0.00452)^2 / (2 * 0.0310)^2 = 2.35.Rate this question:
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- 21.
Which of the following is not an effect of changing Q
- A.
Adding more heat
- B.
Adding a product
- C.
Adding the pressure
- D.
Adding more volume
Correct Answer
A. Adding more heatExplanation
Adding more heat is not an effect of changing Q because Q represents the heat transferred in a chemical reaction. Adding more heat would actually be a way to change Q, rather than an effect of changing it. The other options, adding a product, adding pressure, and adding more volume, are all potential effects of changing Q in a chemical reaction.Rate this question:
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- 22.
Consider the Reaction: A + B <-> C + D Add more C, the reaction will
- A.
Shift left
- B.
Shift Right
- C.
Shift towards less moles
- D.
Shifts towards more moles
Correct Answer
A. Shift leftExplanation
When more C is added to the reaction, according to Le Chatelier's principle, the reaction will shift to the left in order to counteract the increase in C. This means that more A and B will be formed, while the formation of C and D will be reduced. Therefore, the reaction will shift towards the side with fewer moles, which is the left side in this case.Rate this question:
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- 23.
Consider the reaction, A + B <-> C + D The reaction is exothermic, the reaction is then cooled. The reaction shifts?
- A.
Right
- B.
Left
- C.
Towards less moles
- D.
Toward more moles
Correct Answer
A. RightExplanation
When a reaction is exothermic, it means that it releases heat as a product. Cooling the reaction would remove some of this heat, causing the reaction to shift in the direction that produces more heat. Since the forward reaction is exothermic, shifting right means that more heat will be produced, making the reaction shift towards the products (C + D). Therefore, the correct answer is "Right."Rate this question:
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- 24.
If CaCO3, a large solid salt, is added to a reaction, CaCO3 is a product in the reaction, what effect does the addition have to the equilibrium constant?
- A.
The reaction will favor the products
- B.
The reaction will favor the reactants
- C.
There will be no effect
- D.
The reaction will be in equilibrium
Correct Answer
C. There will be no effectExplanation
When CaCO3 is added as a product in the reaction, it does not affect the equilibrium constant. This is because the equilibrium constant only depends on the concentrations of the reactants and products at equilibrium, and adding a solid salt as a product does not change the concentrations of the other species in the reaction. Therefore, the addition of CaCO3 does not shift the equilibrium towards the products or reactants, and the reaction remains in equilibrium.Rate this question:
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- 25.
What do you think the temperature will affect the ammonia synthesis? N2(g) + 3H2(g) ⇌ 2NH3(g) ΔH = −92.4 kJ·mol−1
- A.
Low temperature will help produce more ammonia.
- B.
High temperature will help produce more ammonia.
- C.
Temperature does not affect the ammonia yield.
- D.
None of the above
Correct Answer
A. Low temperature will help produce more ammonia.Explanation
According to Le Chatelier's principle, when the temperature is decreased, the equilibrium will shift in the direction that produces more heat. In this case, the forward reaction is exothermic, meaning it releases heat. Therefore, lowering the temperature will favor the forward reaction, resulting in more ammonia being produced.Rate this question:
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- 26.
In all energy exchanges, if no energy enters or leaves the system, the potential energy of the state will always be less than that of the initial state; in other words; a closed system with temperature and pressure will minimize its energy. This is the definition of?
- A.
None of the answers
- B.
Homogenous Equilibira
- C.
Heterogeneous Equilibria
- D.
Gibbs Free Energy
Correct Answer
A. None of the answers -
- 27.
For the gas-phase oxidation of sulfur dioxide, 2 SO2(g) + O2(g) D 2 SO3(g), Kp = 417 at 200 !C. What is the ΔG! of this reaction at 200?
- A.
-24 kj/mol
- B.
24 kj/mol
- C.
10 kj/mol
- D.
-10 kj/mol
Correct Answer
A. -24 kj/molExplanation
The negative value of ΔG indicates that the reaction is spontaneous in the forward direction at 200°C. This means that the reaction will proceed from left to right, forming more products (SO3) than reactants (SO2 and O2). The magnitude of ΔG (-24 kJ/mol) indicates that the reaction is highly favorable and has a large driving force.Rate this question:
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- 28.
If reaction C = D is at equilibrium with PC=0.5 atm and PD=1.0 atm. Then PC is increased to 1.0 atm while PD remains the same. What is the new equilibrium partial pressure of D?
- A.
1.33 atm
- B.
.67 atm
- C.
1.00 atm
- D.
1.67 atm
Correct Answer
A. 1.33 atmExplanation
When the partial pressure of one reactant is increased while the partial pressure of the other reactant remains the same, the reaction will shift in the direction that reduces the pressure of the reactant that was increased. In this case, since the partial pressure of PC is increased from 0.5 atm to 1.0 atm, the reaction will shift to the right, towards the products. As a result, the partial pressure of D will increase. Since the original partial pressure of D is 1.0 atm and the reaction is at equilibrium, the new equilibrium partial pressure of D will be greater than 1.0 atm. The only option greater than 1.0 atm is 1.33 atm, so that is the correct answer.Rate this question:
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Oct 21, 2024Quiz Edited by
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Jun 02, 2019Quiz Created by
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