Gen Chem II Chemical Equilibrium and Kc Kp
30 flashcards covering Gen Chem II Chemical Equilibrium and Kc Kp for the GENERAL-CHEMISTRY-2 Gen Chem II Topics section.
Chemical equilibrium is a fundamental concept in General Chemistry II, focusing on the dynamic balance between reactants and products in a chemical reaction. This topic is outlined in the curriculum set by the American Chemical Society (ACS), which emphasizes understanding the principles of equilibrium constants (Kc and Kp) and their applications in predicting the behavior of chemical systems.
In practice exams and competency assessments, questions often require students to calculate equilibrium concentrations or to interpret shifts in equilibrium based on changes in conditions, such as concentration, temperature, or pressure. A common pitfall is misunderstanding how to apply Le Chatelier's Principle, leading to incorrect predictions about the direction of shifts in equilibrium. Students frequently misinterpret the effect of temperature changes on Kp and Kc, which can result in errors in calculations and conceptual understanding.
A key tip is to always consider the units of Kc and Kp, as they provide essential information about the reaction conditions and can help avoid miscalculations.
Terms (30)
- 01
What is the equilibrium constant expression for a reaction?
The equilibrium constant expression (Kc) is the ratio of the concentrations of the products raised to their stoichiometric coefficients to the concentrations of the reactants raised to their stoichiometric coefficients at equilibrium. (Zumdahl, Chemical Equilibrium chapter)
- 02
How does temperature affect the value of Kc?
The value of Kc changes with temperature; it is dependent on the specific reaction and the temperature at which it occurs. (Brown LeMay, Chemical Equilibrium chapter)
- 03
What is the relationship between Kc and Kp?
Kp is related to Kc by the equation Kp = Kc(RT)^(Δn), where Δn is the change in moles of gas between products and reactants, R is the ideal gas constant, and T is the temperature in Kelvin. (Tro, Chemical Equilibrium chapter)
- 04
What is the significance of a large Kc value?
A large Kc value indicates that at equilibrium, the concentration of products is much greater than that of reactants, favoring the formation of products. (Brown LeMay, Chemical Equilibrium chapter)
- 05
What does a Kc value of less than 1 indicate?
A Kc value less than 1 indicates that at equilibrium, the concentration of reactants is greater than that of products, favoring the reactants. (Zumdahl, Chemical Equilibrium chapter)
- 06
When is a reaction considered to be at equilibrium?
A reaction is considered to be at equilibrium when the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. (Tro, Chemical Equilibrium chapter)
- 07
How do you calculate Kp from Kc?
Kp can be calculated from Kc using the formula Kp = Kc(RT)^(Δn), where Δn is the change in the number of moles of gas. (Brown LeMay, Chemical Equilibrium chapter)
- 08
What is the effect of adding a catalyst on equilibrium?
Adding a catalyst does not affect the position of equilibrium; it only speeds up the rate at which equilibrium is reached. (Zumdahl, Chemical Equilibrium chapter)
- 09
What is Le Chatelier's principle?
Le Chatelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change. (Tro, Chemical Equilibrium chapter)
- 10
How does increasing the concentration of reactants affect equilibrium?
Increasing the concentration of reactants will shift the equilibrium position to the right, favoring the formation of products. (Brown LeMay, Chemical Equilibrium chapter)
- 11
What happens to equilibrium when the pressure is increased?
Increasing the pressure will shift the equilibrium position toward the side with fewer moles of gas, if the reaction involves gaseous reactants and products. (Zumdahl, Chemical Equilibrium chapter)
- 12
What is the effect of temperature on an exothermic reaction at equilibrium?
For an exothermic reaction, increasing the temperature shifts the equilibrium position to the left, favoring the reactants. (Tro, Chemical Equilibrium chapter)
- 13
What is the equilibrium constant for the reaction A + B ⇌ C + D?
The equilibrium constant Kc for the reaction A + B ⇌ C + D is expressed as Kc = [C][D]/[A][B], where the brackets denote concentrations at equilibrium. (Brown LeMay, Chemical Equilibrium chapter)
- 14
How is Δn calculated in the context of Kp and Kc?
Δn is calculated as the difference between the moles of gaseous products and the moles of gaseous reactants in the balanced chemical equation. (Tro, Chemical Equilibrium chapter)
- 15
What is the effect of removing products on equilibrium?
Removing products from a system at equilibrium will shift the equilibrium position to the right, favoring the formation of more products. (Brown LeMay, Chemical Equilibrium chapter)
- 16
What does it mean if Kp is much greater than Kc?
If Kp is much greater than Kc, it indicates that the reaction produces a significant amount of gaseous products compared to reactants at equilibrium. (Zumdahl, Chemical Equilibrium chapter)
- 17
How often must equilibrium concentrations be measured in a dynamic system?
Equilibrium concentrations are typically measured at specific intervals to ensure that the system has reached a stable state; however, once established, they remain constant unless disturbed. (Tro, Chemical Equilibrium chapter)
- 18
What is a homogeneous equilibrium?
A homogeneous equilibrium is one in which all reactants and products are in the same phase, such as all gases or all liquids. (Brown LeMay, Chemical Equilibrium chapter)
- 19
What is a heterogeneous equilibrium?
A heterogeneous equilibrium involves reactants and products in different phases, such as solids, liquids, and gases. (Zumdahl, Chemical Equilibrium chapter)
- 20
When is Kc temperature dependent?
Kc is temperature dependent for all reactions; its value changes with temperature due to the nature of the reaction and the enthalpy change involved. (Tro, Chemical Equilibrium chapter)
- 21
What is the impact of dilution on equilibrium?
Dilution can affect equilibrium by changing the concentrations of reactants and products, potentially shifting the position of equilibrium depending on the reaction stoichiometry. (Brown LeMay, Chemical Equilibrium chapter)
- 22
What is the formula for calculating Kc for a reaction?
Kc is calculated using the formula Kc = [products]^coefficients / [reactants]^coefficients, where concentrations are at equilibrium. (Zumdahl, Chemical Equilibrium chapter)
- 23
What is the significance of the reaction quotient Q?
The reaction quotient Q is used to determine the direction in which a reaction will proceed to reach equilibrium; if Q < Kc, the reaction shifts right, and if Q > Kc, it shifts left. (Tro, Chemical Equilibrium chapter)
- 24
How does the addition of an inert gas affect equilibrium?
Adding an inert gas at constant volume does not affect the equilibrium position since it does not change the partial pressures of the reacting gases. (Brown LeMay, Chemical Equilibrium chapter)
- 25
What is the relationship between Kc and the stoichiometry of a balanced equation?
Kc is affected by the stoichiometric coefficients of the balanced equation; if the coefficients are multiplied by a factor, Kc is raised to that power. (Zumdahl, Chemical Equilibrium chapter)
- 26
How is Kc affected by a change in volume?
Changing the volume of a system at equilibrium affects the concentrations of gaseous reactants and products, potentially shifting the equilibrium position depending on the reaction stoichiometry. (Tro, Chemical Equilibrium chapter)
- 27
What does it mean if Kc is equal to 1?
If Kc is equal to 1, it indicates that at equilibrium, the concentrations of products and reactants are equal, suggesting neither side is favored. (Brown LeMay, Chemical Equilibrium chapter)
- 28
What is the effect of increasing temperature on an endothermic reaction?
Increasing the temperature of an endothermic reaction shifts the equilibrium position to the right, favoring the formation of products. (Zumdahl, Chemical Equilibrium chapter)
- 29
What is the role of dynamic equilibrium in chemical reactions?
Dynamic equilibrium is a state where the forward and reverse reactions occur at the same rate, resulting in constant concentrations of reactants and products. (Tro, Chemical Equilibrium chapter)
- 30
What happens to the equilibrium constant if the reaction is reversed?
If a reaction is reversed, the new equilibrium constant K' is the reciprocal of the original equilibrium constant K; K' = 1/K. (Brown LeMay, Chemical Equilibrium chapter)