Chemical Equilibrium Concepts
39 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a key characteristic of dynamic equilibrium?

  • There are no particles in motion.
  • The system is closed, and reactions occur at the same rate. (correct)
  • The system is open to matter exchange.
  • Only forward reactions occur.
  • Static equilibrium is characterized by constant motion of particles.

    False (B)

    What principle states that a system will counteract changes made to it in order to restore equilibrium?

    Le Chatelier's Principle

    In the equation for chemical equilibrium, Kc represents the __________ of reactants to products.

    <p>constant</p> Signup and view all the answers

    Match the type of equilibrium with its example:

    <p>Static equilibrium = A seesaw with equal weights on both sides Dynamic equilibrium = A fully occupied restaurant where people are constantly entering and leaving</p> Signup and view all the answers

    Which of the following statements is true regarding Kp and Kc?

    <p>Kc is concerned with concentration while Kp deals with partial pressure. (D)</p> Signup and view all the answers

    Increasing pressure in a reaction favors the side with higher moles of gas.

    <p>False (B)</p> Signup and view all the answers

    What happens to the equilibrium position of the Haber Process if the temperature is lowered?

    <p>The equilibrium shifts to the right, favoring the exothermic forward reaction.</p> Signup and view all the answers

    What does a catalyst do in a chemical reaction?

    <p>Speeds up the rate at which equilibrium is reached (C)</p> Signup and view all the answers

    Temperature can influence the equilibrium constant.

    <p>True (A)</p> Signup and view all the answers

    What is the equilibrium constant (Keq) for the reaction CO(g) + H2O(g) ↔ CO2(g) + H2(g) at 600 K?

    <p>23.2</p> Signup and view all the answers

    At equilibrium, the concentration of CO and H2O will be ______ M.

    <p>0.017</p> Signup and view all the answers

    Match the following reactions with their characteristics:

    <p>CO(g) + H2O(g) ↔ CO2(g) + H2(g) = Contains an equilibrium constant of 23.2 at 600 K CO2 + H2 ↔ CO + H2O = Another reversible reaction H2 + I2 ↔ 2HI = Leads to the formation of hydrochloric acid</p> Signup and view all the answers

    What is represented by the variable x in the calculations for equilibrium?

    <p>The change in concentration for CO and H2O reacting (D)</p> Signup and view all the answers

    A catalyst alters the equilibrium constant of a reaction.

    <p>False (B)</p> Signup and view all the answers

    To find the molar concentration, one must divide the number of moles by the ________.

    <p>volume (in dm3)</p> Signup and view all the answers

    What is the equilibrium constant (K) expression for the reaction H2(g) + I2(g) ⇌ 2 HI(g)?

    <p>K = [HI]^2/[H2][I2] (B)</p> Signup and view all the answers

    The equilibrium constant (K) can change if the temperature of the system is altered.

    <p>True (A)</p> Signup and view all the answers

    Calculate the equilibrium constant (K) if the equilibrium concentrations of NO2 and N2O4 are 0.4 and 0.2 mol dm-3 respectively.

    <p>2.0</p> Signup and view all the answers

    In a 1.00-L container of phosgene, if the concentration of Cl2 is 0.028 M, the concentration of CO will be _____ M.

    <p>0.028</p> Signup and view all the answers

    If the equilibrium constant (Kc) for H2(g) + I2(g) ⇌ 2 HI(g) is given as 50.3 at 731 K, what will happen if the concentrations of H2 and I2 are both introduced at 0.100 M?

    <p>The system will shift to the right to form more HI. (C)</p> Signup and view all the answers

    The equilibrium constant (Kp) has a different expression from Kc for the same reaction.

    <p>True (A)</p> Signup and view all the answers

    What is the value of K if the equilibrium concentrations of the reactants and products lead to a K value greater than 1?

    <p>Products are favored at equilibrium.</p> Signup and view all the answers

    During the decomposition of COCl2(g) to CO(g) and Cl2(g), the initial concentration of COCl2 was _____ M.

    <p>1.00</p> Signup and view all the answers

    Match the following equilibrium constants with their types:

    <p>Kc = Concentration based equilibrium constant Kp = Pressure based equilibrium constant Q = Reaction quotient Keq = General equilibrium constant</p> Signup and view all the answers

    What is the equilibrium expression $K_c$ for the reaction $4NH_3 + 5O_2 ↔ 4NO + 6H_2O$?

    <p>K_c = \frac{[NO]^4}{[NH_3]^4[O_2]^5} (A)</p> Signup and view all the answers

    The addition of more iodine will shift the equilibrium reaction to the right.

    <p>False (B)</p> Signup and view all the answers

    What colour would be observed if the equilibrium position is on the right?

    <p>colourless</p> Signup and view all the answers

    If the temperature of the system is increased and the forward reaction is exothermic, the system will try to ________.

    <p>absorb heat</p> Signup and view all the answers

    What will happen if the pressure of the system with 2NO2 (brown gas) and N2O4 (colourless gas) is increased?

    <p>Colourless gas will be favored. (A)</p> Signup and view all the answers

    Decreasing the temperature favors the forward reaction in an exothermic equilibrium.

    <p>False (B)</p> Signup and view all the answers

    What colour would likely be observed if the pressure is increased in the reaction between NO2 and N2O4?

    <p>colourless</p> Signup and view all the answers

    A catalyst affects the rate of the forward reaction only, True or ________.

    <p>False</p> Signup and view all the answers

    In the event of adding more reactants to a system at equilibrium, what generally occurs?

    <p>The equilibrium shifts towards the products. (C)</p> Signup and view all the answers

    The reaction $2NO_2 ↔ N_2O_4$ has a negative $ riangle H$, indicating it is endothermic.

    <p>False (B)</p> Signup and view all the answers

    What would be the effect on the equilibrium when a catalyst is added?

    <p>It increases the rate of both reactions.</p> Signup and view all the answers

    In an exothermic reaction, increasing the temperature shifts the equilibrium to the ________.

    <p>left</p> Signup and view all the answers

    What would be the expected observation if the equilibrium position is on the left for a given reaction?

    <p>Purple colour (B)</p> Signup and view all the answers

    Match the reaction conditions to the expected outcomes:

    <p>Increasing pressure = Shifts equilibrium to the side with fewer gas molecules Decreasing temperature = Favours exothermic reaction Adding reactants = Shifts equilibrium towards products Adding a catalyst = No change in equilibrium position</p> Signup and view all the answers

    Study Notes

    Equilibrium

    • Equilibrium is a state where the forward and reverse reactions occur at the same rate.
    • Two types of equilibrium: static and dynamic.
    • Static equilibrium: Two equal weights on a seesaw.
    • Dynamic equilibrium: A restaurant with constant occupancy despite people entering and leaving.

    Characteristics of Dynamic Equilibrium

    • Closed system: No matter enters or exits.
    • Constant rate: The forward and reverse reactions occur at the same rate.
    • Macroscopic scale: No noticeable change.
    • Microscopic scale: Constant motion of particles.

    Principles of Chemical Equilibrium

    • Equilibrium constant (K): The ratio of product concentrations to reactant concentrations at a given temperature.
    • General reaction: aA + bB ⇌ cC + dD
    • Equilibrium constant expression: K = [C]c[D]d / [A]a[B]b
    • represents concentration.
    • Kp: Equilibrium constant in terms of partial pressures (for gases only). Solids are excluded.
    • Example: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g)

    Le Chatelier's Principle

    • If a change (stressor) is applied to a system in equilibrium, the system will shift to counteract the change and re-establish equilibrium.
    • Examples: Change in temperature, pressure, or concentration.

    Catalyst

    • Catalysts speed up the rate of both forward and reverse reactions.
    • They do not shift the equilibrium position or the equilibrium constant.
    • They only affect the rate at which equilibrium is reached.

    Temperature Changes

    • Temperature affects the equilibrium constant.

    Pressure Changes

    • If pressure increases, the equilibrium shifts towards the side with fewer moles of gas to reduce pressure.
    • If pressure decreases, the equilibrium shifts towards the side with more moles of gas to increase pressure.

    Haber Process

    • N₂ + 3H₂ ⇌ 2NH₃ ΔH is -ve, meaning the forward reaction is exothermic.
    • Lowering the temperature favors the exothermic forward reaction thus increasing the yield of ammonia.
    • Increasing pressure favors the side with fewer moles of gas (the right side), also increases the ammonia yield.

    Contact Process

    • Similar to Haber process, system shifts to counteract applied pressure change.

    Equilibrium Calculations

    • ICE tables (Initial, Change, Equilibrium) are useful tools for calculating equilibrium concentrations.
      • Used to solve for unknown quantities upon adding reactants or products to existing equilibrium conditions.

    Equilibrium Constant, Kc

    • Equilibrium constant for a given reaction at a defined temperature.
    • Used to determine how much reactants/products are at equilibrium.
    • Value determined based on amounts of products/reactants.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Description

    This quiz explores the fundamental concepts of chemical equilibrium, including the types and characteristics of equilibrium states. Delve into the principles of dynamic equilibrium and learn about the equilibrium constant and its expressions. Test your understanding of how equilibrium applies to various chemical reactions.

    More Like This

    Use Quizgecko on...
    Browser
    Browser