Podcast
Questions and Answers
Which type of system allows both matter and energy to be exchanged with its surroundings?
Which type of system allows both matter and energy to be exchanged with its surroundings?
- A closed system
- An adiabatic system
- An open system (correct)
- An isolated system
Which of the following best describes a closed system?
Which of the following best describes a closed system?
- Exchanges matter but not energy with the surroundings
- Exchanges both matter and energy with the surroundings
- Exchanges energy but not matter with the surroundings (correct)
- Exchanges neither matter nor energy with the surroundings
What is a key characteristic of a system at chemical equilibrium?
What is a key characteristic of a system at chemical equilibrium?
- The concentration of reactants is zero.
- The reaction stops completely.
- The rates of the forward and reverse reactions are equal. (correct)
- The concentration of products decreases over time.
Which of the following is true for a reaction at dynamic equilibrium?
Which of the following is true for a reaction at dynamic equilibrium?
What does Le Chtelier's Principle state?
What does Le Chtelier's Principle state?
For the reaction (\text{N}_2(g) + 3 ext{H}_2(g)
ightleftharpoons 2 ext{NH}_3(g)), how will increasing pressure affect the equilibrium?
For the reaction (\text{N}_2(g) + 3 ext{H}_2(g) ightleftharpoons 2 ext{NH}_3(g)), how will increasing pressure affect the equilibrium?
How does increasing the temperature affect an exothermic reaction at equilibrium?
How does increasing the temperature affect an exothermic reaction at equilibrium?
What effect does adding more reactants have on a system at equilibrium?
What effect does adding more reactants have on a system at equilibrium?
In industrial processes like the Haber process, how are equilibrium principles applied?
In industrial processes like the Haber process, how are equilibrium principles applied?
Which expression represents the equilibrium constant (K_{eq}) for the general reaction (aA + bB
ightleftharpoons cC + dD)?
Which expression represents the equilibrium constant (K_{eq}) for the general reaction (aA + bB ightleftharpoons cC + dD)?
What does the value of (K_{eq}) indicate about the relative amounts of reactants and products at equilibrium?
What does the value of (K_{eq}) indicate about the relative amounts of reactants and products at equilibrium?
The equilibrium constant, Kc, is derived from which law?
The equilibrium constant, Kc, is derived from which law?
For the reaction (aA + bB cC + dD), what do [A], [B], [C], and [D] represent in the expression for (K_c)?
For the reaction (aA + bB cC + dD), what do [A], [B], [C], and [D] represent in the expression for (K_c)?
Which factor directly influences the value of (K_c)?
Which factor directly influences the value of (K_c)?
How do catalysts affect the equilibrium constant, (K_c)?
How do catalysts affect the equilibrium constant, (K_c)?
For the reaction (2A(g) + B(g) 3C(g)), what is the value of (K_c) if ([A] = 0.2 , M), ([B] = 0.3 , M), and ([C] = 0.5 , M) at equilibrium?
For the reaction (2A(g) + B(g) 3C(g)), what is the value of (K_c) if ([A] = 0.2 , M), ([B] = 0.3 , M), and ([C] = 0.5 , M) at equilibrium?
What does a high (K_c) value ((K_c > 1)) indicate about the equilibrium position?
What does a high (K_c) value ((K_c > 1)) indicate about the equilibrium position?
What does a low (K_c) value ((0 < K_c < 1)) suggest about the equilibrium?
What does a low (K_c) value ((0 < K_c < 1)) suggest about the equilibrium?
In the context of the Haber process, how is the (K_c) value utilized?
In the context of the Haber process, how is the (K_c) value utilized?
How is understanding equilibrium critical in environmental chemistry?
How is understanding equilibrium critical in environmental chemistry?
According to Le Chatelier's principle, what happens when the concentration of reactants is increased in a system at equilibrium?
According to Le Chatelier's principle, what happens when the concentration of reactants is increased in a system at equilibrium?
How does increasing the temperature affect the equilibrium of an endothermic reaction?
How does increasing the temperature affect the equilibrium of an endothermic reaction?
For gaseous reactions, how does increasing pressure (by decreasing volume) affect the equilibrium according to Le Chatelier's principle?
For gaseous reactions, how does increasing pressure (by decreasing volume) affect the equilibrium according to Le Chatelier's principle?
What does a flat line on a graph of concentration versus time indicate for a system at equilibrium?
What does a flat line on a graph of concentration versus time indicate for a system at equilibrium?
In the Haber process for ammonia production, what conditions are typically used to increase the yield?
In the Haber process for ammonia production, what conditions are typically used to increase the yield?
In the Contact process for sulfuric acid production, how is the yield of sulfur trioxide maximized?
In the Contact process for sulfuric acid production, how is the yield of sulfur trioxide maximized?
Which of the following changes will shift the equilibrium to the right in the following reaction: (A(g) + B(g)
ightleftharpoons C(g) + Heat)?
Which of the following changes will shift the equilibrium to the right in the following reaction: (A(g) + B(g) ightleftharpoons C(g) + Heat)?
Consider the reaction: (2SO_2(g) + O_2(g)
ightleftharpoons 2SO_3(g)) (\Delta H = -198 \text{ kJ/mol}). Which change will NOT increase the amount of (SO_3(g)) at equilibrium?
Consider the reaction: (2SO_2(g) + O_2(g) ightleftharpoons 2SO_3(g)) (\Delta H = -198 \text{ kJ/mol}). Which change will NOT increase the amount of (SO_3(g)) at equilibrium?
Given the reaction (A(g) + B(g)
ightleftharpoons 2C(g)), at a certain temperature, the equilibrium constant (K_c) is 4. If 1 mole of A and 1 mole of B are allowed to react in a 1-liter container, what is the equilibrium concentration of C?
Given the reaction (A(g) + B(g) ightleftharpoons 2C(g)), at a certain temperature, the equilibrium constant (K_c) is 4. If 1 mole of A and 1 mole of B are allowed to react in a 1-liter container, what is the equilibrium concentration of C?
For the reaction (N_2O_4(g)
ightleftharpoons 2NO_2(g)), the system is initially at equilibrium. Then, some (NO_2) is suddenly added. Which of the following statements is correct regarding the changes just after the addition?
For the reaction (N_2O_4(g) ightleftharpoons 2NO_2(g)), the system is initially at equilibrium. Then, some (NO_2) is suddenly added. Which of the following statements is correct regarding the changes just after the addition?
A closed vessel contains equal moles of (PCl_5), (Cl_2), and (PCl_3). The pressure is increased by adding helium gas. What happens to the equilibrium of: (PCl_5(g)
ightleftharpoons PCl_3(g) + Cl_2(g))?
A closed vessel contains equal moles of (PCl_5), (Cl_2), and (PCl_3). The pressure is increased by adding helium gas. What happens to the equilibrium of: (PCl_5(g) ightleftharpoons PCl_3(g) + Cl_2(g))?
The endothermic reaction (2X(g)
ightleftharpoons Y(g) + Z(g)) is performed. Which direction will the equilibrium shift with (1) increasing total pressure and (2) with adding an inert gas at constant pressure?
The endothermic reaction (2X(g) ightleftharpoons Y(g) + Z(g)) is performed. Which direction will the equilibrium shift with (1) increasing total pressure and (2) with adding an inert gas at constant pressure?
A system that does not allow the transfer of matter, but does allow the transfer of energy is best described as:
A system that does not allow the transfer of matter, but does allow the transfer of energy is best described as:
Which of the following is a characteristic of dynamic equilibrium?
Which of the following is a characteristic of dynamic equilibrium?
Consider the reversible reaction: $A + B \rightleftharpoons C$. If the concentration of A is increased, what change will likely occur?
Consider the reversible reaction: $A + B \rightleftharpoons C$. If the concentration of A is increased, what change will likely occur?
For the exothermic reaction $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$, which change will not increase the production of $SO_3(g)$?
For the exothermic reaction $2SO_2(g) + O_2(g) \rightleftharpoons 2SO_3(g)$, which change will not increase the production of $SO_3(g)$?
A container holds gases A, B, and C in equilibrium according to the reaction $A(g) + B(g) \rightleftharpoons C(g)$. If the volume of the container is suddenly decreased, thus increasing the pressure, what will happen to the equilibrium?
A container holds gases A, B, and C in equilibrium according to the reaction $A(g) + B(g) \rightleftharpoons C(g)$. If the volume of the container is suddenly decreased, thus increasing the pressure, what will happen to the equilibrium?
The equilibrium constant, $K_{eq}$, for a reaction is 100 at $25^\circ C$. What does this suggest about the reaction?
The equilibrium constant, $K_{eq}$, for a reaction is 100 at $25^\circ C$. What does this suggest about the reaction?
For the reaction $A(g) + B(g) \rightleftharpoons C(g)$, $K_c = 4$. If 2 moles of C are placed in a 1L container, which way will the reaction shift?
For the reaction $A(g) + B(g) \rightleftharpoons C(g)$, $K_c = 4$. If 2 moles of C are placed in a 1L container, which way will the reaction shift?
What is the effect of a catalyst on a reversible reaction at equilibrium?
What is the effect of a catalyst on a reversible reaction at equilibrium?
In an endothermic reaction at equilibrium, what is the effect of increasing the temperature?
In an endothermic reaction at equilibrium, what is the effect of increasing the temperature?
What does a very small value of ( K_c ) (much less than 1) indicate about a reversible reaction at equilibrium?
What does a very small value of ( K_c ) (much less than 1) indicate about a reversible reaction at equilibrium?
For the gaseous reaction $A + B \rightleftharpoons 2C$, the initial partial pressures are $P_A = 2$ atm, $P_B = 2$ atm, and $P_C = 4$ atm. After equilibrium is established, the partial pressure of B is found to be 3 atm. What is the value of $K_p$ for this reaction?
For the gaseous reaction $A + B \rightleftharpoons 2C$, the initial partial pressures are $P_A = 2$ atm, $P_B = 2$ atm, and $P_C = 4$ atm. After equilibrium is established, the partial pressure of B is found to be 3 atm. What is the value of $K_p$ for this reaction?
Consider the reaction $2A(g) + B(g) \rightleftharpoons 3C(g)$. At a certain temperature, ( K_c = 4 ). If a sealed container initially contains 2.0 M of A and 2.0 M of B, what is the equilibrium concentration of C?
Consider the reaction $2A(g) + B(g) \rightleftharpoons 3C(g)$. At a certain temperature, ( K_c = 4 ). If a sealed container initially contains 2.0 M of A and 2.0 M of B, what is the equilibrium concentration of C?
How does increasing the total pressure on a system affect the equilibrium position in the reaction $N_2(g) + O_2(g) \rightleftharpoons 2NO(g)$?
How does increasing the total pressure on a system affect the equilibrium position in the reaction $N_2(g) + O_2(g) \rightleftharpoons 2NO(g)$?
What is the correct expression for the equilibrium constant (K_c) for the reaction: $2A(s) + B(g) \rightleftharpoons 2C(g) + D(s)$?
What is the correct expression for the equilibrium constant (K_c) for the reaction: $2A(s) + B(g) \rightleftharpoons 2C(g) + D(s)$?
For the reaction $A(g) \rightleftharpoons B(g) + C(g)$, the equilibrium constant (K_p) is found to be 2. What does this indicate about the standard Gibbs free energy change (( \Delta G^\circ )) for this reaction?
For the reaction $A(g) \rightleftharpoons B(g) + C(g)$, the equilibrium constant (K_p) is found to be 2. What does this indicate about the standard Gibbs free energy change (( \Delta G^\circ )) for this reaction?
Consider the equilibrium: $A(g) + B(g) \rightleftharpoons C(g)$. At a given temperature, the value of (K_c) is dependent on:
Consider the equilibrium: $A(g) + B(g) \rightleftharpoons C(g)$. At a given temperature, the value of (K_c) is dependent on:
Which of the following actions will always increase the amount of product in a reaction at equilibrium?
Which of the following actions will always increase the amount of product in a reaction at equilibrium?
For an endothermic reaction, how does (K_c) change as temperature increases?
For an endothermic reaction, how does (K_c) change as temperature increases?
If (K_c = 0.01) for the reaction $A(g) \rightleftharpoons B(g)$, what can be said about the rate constants of the forward ((k_f)) and reverse ((k_r)) reactions?
If (K_c = 0.01) for the reaction $A(g) \rightleftharpoons B(g)$, what can be said about the rate constants of the forward ((k_f)) and reverse ((k_r)) reactions?
The reaction $A(g) + B(g) \rightleftharpoons C(g)$ has an equilibrium constant (K_c) of 0.2. Starting with 2 moles of A and 2 moles of B in a 1 liter container, what is the equilibrium concentration of C?
The reaction $A(g) + B(g) \rightleftharpoons C(g)$ has an equilibrium constant (K_c) of 0.2. Starting with 2 moles of A and 2 moles of B in a 1 liter container, what is the equilibrium concentration of C?
How does the addition of an inert gas at constant volume affect the equilibrium of a reaction?
How does the addition of an inert gas at constant volume affect the equilibrium of a reaction?
Consider the equilibrium: $2NO(g) + O_2(g) \rightleftharpoons 2NO_2(g)$. If the volume of the container is doubled, how will the equilibrium shift?
Consider the equilibrium: $2NO(g) + O_2(g) \rightleftharpoons 2NO_2(g)$. If the volume of the container is doubled, how will the equilibrium shift?
For the reaction $A + B \rightleftharpoons C + D$, what effect does decreasing the volume of the container have on the equilibrium constant, (K_c)?
For the reaction $A + B \rightleftharpoons C + D$, what effect does decreasing the volume of the container have on the equilibrium constant, (K_c)?
At equilibrium, what is true about the Gibbs Free Energy?
At equilibrium, what is true about the Gibbs Free Energy?
Which of the following statements is correct regarding the relationship between (K_c) and (K_p) for a reaction where the number of moles of gaseous reactants equals the number of moles of gaseous products?
Which of the following statements is correct regarding the relationship between (K_c) and (K_p) for a reaction where the number of moles of gaseous reactants equals the number of moles of gaseous products?
A reaction has ( \Delta H < 0 ) and ( \Delta S < 0 ). Which condition favors the products at equilibrium?
A reaction has ( \Delta H < 0 ) and ( \Delta S < 0 ). Which condition favors the products at equilibrium?
Le Chatelier's principle is best applied to:
Le Chatelier's principle is best applied to:
The Contact process is used for the industrial production of:
The Contact process is used for the industrial production of:
Consider a reaction in a closed container at equilibrium. If the temperature is increased, and the equilibrium shifts towards the reactants, what can be said about the reaction?
Consider a reaction in a closed container at equilibrium. If the temperature is increased, and the equilibrium shifts towards the reactants, what can be said about the reaction?
What is the primary industrial application of the Haber process?
What is the primary industrial application of the Haber process?
A system is at equilibrium when:
A system is at equilibrium when:
The synthesis of substance C is represented by (A + B \rightleftharpoons C). You are given (K_c = 10^{-7}) at 298 K. To improve the product field, which of the following is the best approach?
The synthesis of substance C is represented by (A + B \rightleftharpoons C). You are given (K_c = 10^{-7}) at 298 K. To improve the product field, which of the following is the best approach?
Suppose we have the system, (A + B \rightleftharpoons C), with (K_c < 1). Someone proposes that increasing the concentration of A by a factor of 10 will increase the concentration of C by a factor close to 10 at equilibrium. How would you respond to this proposal?
Suppose we have the system, (A + B \rightleftharpoons C), with (K_c < 1). Someone proposes that increasing the concentration of A by a factor of 10 will increase the concentration of C by a factor close to 10 at equilibrium. How would you respond to this proposal?
In an open system, what kinds of exchange occur with the surroundings?
In an open system, what kinds of exchange occur with the surroundings?
Which type of system is exemplified by a sealed flask where a chemical reaction takes place?
Which type of system is exemplified by a sealed flask where a chemical reaction takes place?
What characterizes a reversible reaction?
What characterizes a reversible reaction?
Consider the Haber process: ( ext{N}_2(g) + 3 ext{H}_2(g)
ightleftharpoons 2 ext{NH}_3(g)). What does the double arrow indicate?
Consider the Haber process: ( ext{N}_2(g) + 3 ext{H}_2(g) ightleftharpoons 2 ext{NH}_3(g)). What does the double arrow indicate?
What condition defines chemical equilibrium?
What condition defines chemical equilibrium?
What is meant by the term dynamic equilibrium?
What is meant by the term dynamic equilibrium?
Which of the following describes a homogeneous reaction?
Which of the following describes a homogeneous reaction?
What characterizes a heterogeneous reaction?
What characterizes a heterogeneous reaction?
According to Le Chtelier's Principle, how will a system at equilibrium respond to an imposed change?
According to Le Chtelier's Principle, how will a system at equilibrium respond to an imposed change?
For the reaction ( ext{N}_2(g) + 3 ext{H}_2(g)
ightleftharpoons 2 ext{NH}_3(g)), how does increasing pressure affect the equilibrium?
For the reaction ( ext{N}_2(g) + 3 ext{H}_2(g) ightleftharpoons 2 ext{NH}_3(g)), how does increasing pressure affect the equilibrium?
How will adding more reactants to a system at equilibrium affect the position of the equilibrium?
How will adding more reactants to a system at equilibrium affect the position of the equilibrium?
In the context of chemical equilibrium, what effect does a catalyst have on the equilibrium constant ((K_{eq}))?
In the context of chemical equilibrium, what effect does a catalyst have on the equilibrium constant ((K_{eq}))?
What is the primary application of understanding chemical equilibrium in the pharmaceutical industry?
What is the primary application of understanding chemical equilibrium in the pharmaceutical industry?
How is the concept of chemical equilibrium used in addressing climate change?
How is the concept of chemical equilibrium used in addressing climate change?
The equilibrium constant (K_c) is expressed as the ratio of:
The equilibrium constant (K_c) is expressed as the ratio of:
For a certain reaction the equilibrium constant is much larger than 1. What does this indicate about the reaction?
For a certain reaction the equilibrium constant is much larger than 1. What does this indicate about the reaction?
If (K_c) for a reaction is less than 1, what does this indicate?
If (K_c) for a reaction is less than 1, what does this indicate?
How does temperature influence the equilibrium constant, (K_c)?
How does temperature influence the equilibrium constant, (K_c)?
Which of the following factors does not directly influence the value of (K_c)?
Which of the following factors does not directly influence the value of (K_c)?
Consider a reaction at equilibrium. What does a flat line on a graph of concentration versus time indicate?
Consider a reaction at equilibrium. What does a flat line on a graph of concentration versus time indicate?
What is the relationship between the rates of the forward and reverse reactions at equilibrium?
What is the relationship between the rates of the forward and reverse reactions at equilibrium?
Using Le Chtelier's principle, predict how increasing the concentration of reactants will affect a system at equilibrium.
Using Le Chtelier's principle, predict how increasing the concentration of reactants will affect a system at equilibrium.
How does decreasing the volume (increasing pressure) affect a gaseous reaction at equilibrium according to Le Chatelier's principle?
How does decreasing the volume (increasing pressure) affect a gaseous reaction at equilibrium according to Le Chatelier's principle?
In an industrial process, conditions are adjusted to control the equilibrium position in order to:
In an industrial process, conditions are adjusted to control the equilibrium position in order to:
Consider the reaction: $2A(g) + B(g) \rightleftharpoons 3C(g)$. Given equilibrium concentrations of $[A] = 0.2 , M$, $[B] = 0.3 , M$, and $[C] = 0.5 , M$, calculate the equilibrium constant (K_c).
Consider the reaction: $2A(g) + B(g) \rightleftharpoons 3C(g)$. Given equilibrium concentrations of $[A] = 0.2 , M$, $[B] = 0.3 , M$, and $[C] = 0.5 , M$, calculate the equilibrium constant (K_c).
For the Haber process, what conditions are typically optimized to maximize the production of ammonia?
For the Haber process, what conditions are typically optimized to maximize the production of ammonia?
What conditions maximize the yield of sulfur trioxide in the Contact process for sulfuric acid production?
What conditions maximize the yield of sulfur trioxide in the Contact process for sulfuric acid production?
A reaction has the equilibrium constant (K_c = 0.5) at a given temperature. Initially, a container is filled with 2.0 M of reactant A. At equilibrium, what should be expected to be the concentration of A?
A reaction has the equilibrium constant (K_c = 0.5) at a given temperature. Initially, a container is filled with 2.0 M of reactant A. At equilibrium, what should be expected to be the concentration of A?
In the reaction $ A(g) + B(g) \rightleftharpoons C(g) $, a catalyst is added. How does this affect the equilibrium?
In the reaction $ A(g) + B(g) \rightleftharpoons C(g) $, a catalyst is added. How does this affect the equilibrium?
A 1.0 L flask is filled with 2.0 mol of (H_2) and 2.0 mol of (I_2) at 448C. The value of (K_c) for the reaction (H_{2(g)} + I_{2(g)}
ightleftharpoons 2HI_{(g)}) at 448C is 50.3. What is the equilibrium concentration of HI?
A 1.0 L flask is filled with 2.0 mol of (H_2) and 2.0 mol of (I_2) at 448C. The value of (K_c) for the reaction (H_{2(g)} + I_{2(g)} ightleftharpoons 2HI_{(g)}) at 448C is 50.3. What is the equilibrium concentration of HI?
For the reaction, $A(g) + B(g)
ightleftharpoons C(g)$, what effect does decreasing the volume of the container have on the equilibrium constant, (K_c)?
For the reaction, $A(g) + B(g) ightleftharpoons C(g)$, what effect does decreasing the volume of the container have on the equilibrium constant, (K_c)?
Consider the endothermic reaction $A
ightleftharpoons B$. You start with only A in a closed container. Which of the following actions will always increase the amount of B at equilibrium?
Consider the endothermic reaction $A ightleftharpoons B$. You start with only A in a closed container. Which of the following actions will always increase the amount of B at equilibrium?
Suppose (K_c = 0.01) for the reaction $A
ightleftharpoons B$. This implies the rate constant of the forward reaction ((k_f)) and reverse reaction ((k_r)) are such that:
Suppose (K_c = 0.01) for the reaction $A ightleftharpoons B$. This implies the rate constant of the forward reaction ((k_f)) and reverse reaction ((k_r)) are such that:
At a certain temperature, (K_c = 1.6 \times 10^{-5}) for the reaction $2NOCl(g) \rightleftharpoons 2NO(g) + Cl_2(g)$. Consider an equilibrium mixture with concentrations $[NOCl] = 0.50 M$ and $[NO] = 1.2 \times 10^{-3} M$. What is the concentration of (Cl_2) in this mixture?
At a certain temperature, (K_c = 1.6 \times 10^{-5}) for the reaction $2NOCl(g) \rightleftharpoons 2NO(g) + Cl_2(g)$. Consider an equilibrium mixture with concentrations $[NOCl] = 0.50 M$ and $[NO] = 1.2 \times 10^{-3} M$. What is the concentration of (Cl_2) in this mixture?
Flashcards
Open System
Open System
A system where both matter and energy are exchanged with the surroundings.
Closed System
Closed System
A system where energy can be transferred, but matter is not exchanged with the surroundings.
Reversible Reactions
Reversible Reactions
Reactions where products can react to regenerate the original reactants.
Chemical Equilibrium
Chemical Equilibrium
State where the rate of the forward reaction equals the rate of the reverse reaction, resulting in constant concentrations of reactants and products.
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Homogeneous Reactions
Homogeneous Reactions
Reactions involving reactants and products in the same phase.
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Heterogeneous Reactions
Heterogeneous Reactions
Reactions involving reactants and products in different phases.
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Le Châtelier's Principle
Le Châtelier's Principle
A system at equilibrium will adjust to counteract any changes imposed on it.
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Shifting Equilibrium Towards Products
Shifting Equilibrium Towards Products
Adding more reactants or removing products.
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Shifting Equilibrium Towards Reactants
Shifting Equilibrium Towards Reactants
Removing reactants or adding products.
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Temperature Effect on Equilibrium
Temperature Effect on Equilibrium
Raising the temperature favors the endothermic direction, while lowering the temperature favors the exothermic direction.
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Le Châtelier's Principle
Le Châtelier's Principle
Principle stating a system at equilibrium will shift its position to counteract changes in pressure, concentration, or temperature.
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Equilibrium Constant (Keq)
Equilibrium Constant (Keq)
The ratio of product concentrations to reactant concentrations at equilibrium, each raised to the power of their stoichiometric coefficients.
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Equilibrium Constant (Kc)
Equilibrium Constant (Kc)
Quantifies the position of equilibrium, giving a numerical measure of the extent to which a reaction proceeds.
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Kc and Temperature
Kc and Temperature
Temperature-dependent. Changing the temperature will shift the equilibrium position, thus changing the Kc value.
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Catalysts and Kc
Catalysts and Kc
Accelerate the rate at which equilibrium is reached but do not affect the equilibrium constant, Kc, as they lower the activation energy for both forward and reverse reactions equally.
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RICE Table Method
RICE Table Method
A method used to calculate the equilibrium concentrations involving initial concentrations and changes
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High Kc Value (Kc > 1)
High Kc Value (Kc > 1)
Indicates that the equilibrium position favors the products. At equilibrium, the concentration of products is much higher than that of the reactants
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Low Kc Value (0 < Kc < 1)
Low Kc Value (0 < Kc < 1)
Suggests that the equilibrium favors the reactants. Only a small amount of product is formed, and most of the reactants remain unreacted at equilibrium.
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Le Chatelier's principle
Le Chatelier's principle
When a system at equilibrium is subjected to a change the system adjusts to counteract the imposed change and restore a new equilibrium.
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Increasing the concentration of reactants
Increasing the concentration of reactants
Shifts the equilibrium towards the products, increasing product formation.
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Increasing the concentration of products
Increasing the concentration of products
Shifts the equilibrium towards the reactants, reducing product formation.
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Increasing the temperature for exothermic reactions
Increasing the temperature for exothermic reactions
Shifts the equilibrium towards the reactants, reducing product yield.
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Increasing the temperature for endothermic reactions
Increasing the temperature for endothermic reactions
Shifts the equilibrium towards the products, increasing product yield.
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Increasing pressure for gaseous reactions
Increasing pressure for gaseous reactions
Shifts the equilibrium towards the side with fewer gas molecules.
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Decreasing pressure for gaseous reactions
Decreasing pressure for gaseous reactions
Shifts the equilibrium towards the side with more gas molecules.
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Flat line on Equilibrium Graphs
Flat line on Equilibrium Graphs
Indicates that the system has reached equilibrium.
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Sudden Change in Slope
Sudden Change in Slope
Indicates a disturbance, such as a change in concentration or temperature.
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Effect of Pressure on Gases
Effect of Pressure on Gases
Favors the side with fewer gas molecules when pressure increases.
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Endothermic Reaction
Endothermic Reaction
Reaction that absorbs heat from the surroundings.
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Exothermic Reaction
Exothermic Reaction
Reaction that releases heat into the surroundings.
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Haber Process
Haber Process
Used to optimize ammonia yield.
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Pharmaceuticals: Equilibrium principles
Pharmaceuticals: Equilibrium principles
Maximize the yield of desired products minimizing waste.
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High Kc value
High Kc value
Indicates products are highly favored at equilibrium.
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Low Kc value
Low Kc value
Indicates reactants are favored at equilibrium.
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Haber Process
Haber Process
Industrial ammonia synthesis process.
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Contact Process
Contact Process
Industrial sulfuric acid production.
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Increased Pressure (Gases)
Increased Pressure (Gases)
Shifts the equilibrium toward the side with fewer gas molecules.
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Pharmaceutical Applications
Pharmaceutical Applications
The study of equilibrium to maximize product creation and minimize waste.
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Dynamic Equilibrium
Dynamic Equilibrium
Indicates that the forward and reverse reaction rates are equal and the concentrations of reactants and products are constant.
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Chemical Equilibrium: Fundamental Concepts and Influences
- Chemical equilibrium is crucial for understanding reversible reactions in academic studies and practical applications like industrial processes, environmental systems, and biological mechanisms.
Open and Closed Systems in Chemistry
- Open Systems: Exchange both matter and energy with the surroundings (e.g., boiling pot of water without a lid).
- Closed Systems: Transfer energy but do not exchange matter with the surroundings (e.g., sealed flask).
Reversible Reactions
- Products react to regenerate original reactants, indicated by a double-headed arrow (⇌).
- Example: Haber process for ammonia synthesis: (\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)).
Chemical Equilibrium
- Achieved when the rate of the forward reaction equals the rate of the reverse reaction.
- Dynamic equilibrium: Concentrations of reactants and products remain constant, with ongoing reactions but no net change in concentrations.
Homogeneous and Heterogeneous Reactions
- Homogeneous Reactions: Reactants and products are in the same phase (e.g., gases reacting to form a gas).
- Heterogeneous Reactions: Reactants and products are in different phases (e.g., solid reacting with a gas to produce a solid and a gas).
Factors Influencing the Position of Chemical Equilibrium
- Le Châtelier's Principle: A system at equilibrium adjusts to counteract imposed changes.
- Pressure (for gases): Increasing pressure shifts equilibrium toward the side with fewer gas molecules.
- Concentration: Adding reactants or removing products shifts equilibrium toward the products, and vice versa.
- Temperature: Raising temperature favors endothermic reactions; lowering temperature favors exothermic reactions.
Le Châtelier's Principle
- Predicts how a system at equilibrium responds to disturbances like changes in pressure, concentration, or temperature by opposing the change.
- Example: Adding reactants shifts equilibrium toward the products.
- Example: Raising the temperature of an exothermic reaction shifts it toward the reactants.
Application and Examples
- Haber Process: Optimizing pressure and temperature increases ammonia yields.
- Pharmaceuticals: Equilibrium principles maximize desired product yield and minimize waste.
- Environmental Systems: Understanding equilibria is critical for addressing climate change (e.g., carbon dioxide exchange between atmosphere and oceans).
Quantitative Aspects
- Equilibrium constant (K_{eq}): Ratio of product to reactant concentrations at equilibrium, each raised to the power of their stoichiometric coefficients.
- For a general reaction: (\text{aA} + \text{bB} \rightleftharpoons \text{cC} + \text{dD}), the equilibrium constant is (K_{eq} = \frac{[\text{C}]^c [\text{D}]^d}{[\text{A}]^a [\text{B}]^b}).
- The value of (K_{eq}) indicates the relative amounts of reactants and products at equilibrium.
Equilibrium Constant (Kc)
- The equilibrium constant (Kc) is derived from the Law of Mass Action, stating reactant and product concentrations remain constant at equilibrium at a given temperature.
- Kc quantifies the position of equilibrium and offers a numerical measure of how far a reaction proceeds.
Definition and Expression
- For a general reaction: (\text{aA} + \text{bB} ⇌ \text{cC} + \text{dD})
- Equilibrium constant expression: (K_c = \frac{[\text{C}]^c [\text{D}]^d}{[\text{A}]^a [\text{B}]^b})
- ([A]), ([B]), ([C]), and ([D]) are the molar concentrations of reactants and products at equilibrium.
- (a), (b), (c), and (d) are the stoichiometric coefficients from the balanced equation.
Factors Influencing Kc
- Temperature: Kc is temperature-dependent; increasing temperature lowers Kc for exothermic reactions and increases it for endothermic reactions.
- Nature of the Reaction: Molecular interactions, energy states, and bond strengths affect Kc.
- Pressure and Volume: Changes in pressure or volume influence the equilibrium position of gaseous reactions.
- Catalysts: Accelerate equilibrium but do not affect Kc.
Calculation of Kc
- Molar concentrations of reactants and products at equilibrium are needed to calculate Kc.
- Substitute known values into the equilibrium expression to solve for Kc.
Significance of High and Low Kc Values
- High Kc Value (Kc > 1): Indicates equilibrium favors products, meaning a highly efficient reaction with significant product amounts; e.g., Haber process at optimal conditions.
- Low Kc Value (0 < Kc < 1): Indicates equilibrium favors reactants, a small amount of product forms, and most reactants remain; e.g., dissociation of weak acids.
Industrial and Environmental Implications
- Industrial Chemistry: Controlling equilibrium is crucial for maximizing product yield (e.g., optimized conditions in the Haber process).
- Environmental and Biological Relevance: Understanding equilibrium is critical for processes like carbon dioxide exchange in oceans (climate change) and biological equilibria in metabolic pathways.
Application of Equilibrium Principles
- Le Chatelier's principle helps manipulate chemical reactions, especially in industrial processes, by understanding how changes in conditions shift equilibrium.
Le Chatelier's Principle
- When a system at equilibrium faces changes in concentration, temperature, or pressure, it adjusts to counteract the change and restore equilibrium.
Applying Le Chatelier's Principle
- Changes in Concentration:
- Increasing reactants shifts equilibrium toward products.
- Increasing products shifts equilibrium toward reactants.
- Changes in Temperature:
- Exothermic reactions: Increasing temperature shifts equilibrium toward reactants.
- Endothermic reactions: Increasing temperature shifts equilibrium toward products.
- Changes in Pressure (for gaseous reactions):
- Increasing pressure shifts equilibrium toward fewer gas molecules.
- Decreasing pressure shifts equilibrium toward more gas molecules.
Interpreting Graphs of Equilibrium
- Graphs of concentration, rate, moles, mass, or volume over time show how equilibrium shifts.
- A flat line indicates equilibrium.
- A sudden slope change indicates a disturbance.
- The shift direction is deduced from graph changes.
Industrial Applications: Haber and Contact Processes
- Haber Process (ammonia production):
- Optimal conditions: high pressure, moderate temperature, catalyst.
- Applying Le Chatelier’s principle: increase pressure and use optimal temperature.
- Contact Process (sulfuric acid production):
- Involves oxidation of sulfur dioxide to sulfur trioxide.
- Maximize sulfur trioxide yield by increasing pressure and maintaining moderate temperature.
Practical Examples and Calculations
- Graph Analysis:
- Analyzing rate vs. time and concentration vs. time graphs identifies when equilibrium is reached and response to changes.
- Calculations Based on Changes:
- Equilibrium calculations involve changes in concentration, pressure, or temperature and their effects on Kc and reaction yields.
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