Chemical Equilibrium & Ionic Equilibrium |JEE Mains 2nd Attempt |All Concepts & PYQs |Nabamita Mam

Vedantu JEE English・2 minutes read

The text discusses chemical and ionic equilibrium, including types of reactions, reversible vs. irreversible reactions, equilibrium constants, and factors influencing equilibrium, such as temperature, concentration changes, and pressure alterations. It delves into concepts like physical and dynamic equilibrium, Haber's process, and the relationship between Gibbs free energy and equilibrium constant, highlighting how external stress and changes in concentration, pressure, volume, and temperature affect equilibrium.

Insights

  • 1. Different reactions, like reversible and irreversible ones, exhibit varying characteristics: Reversible reactions involve bidirectional conversion of reactants to products, while irreversible reactions only proceed in one direction, impacting the attainment of equilibrium differently.
  • 2. Equilibrium constants play a pivotal role in understanding reaction dynamics: Equilibrium constants, such as KC and KP, are essential for predicting reaction extent and direction, with factors like stoichiometry and temperature influencing their values significantly.
  • 3. External stressors and Le Chatelier's principle impact equilibrium: Changes in concentration, pressure, volume, temperature, or inert gas addition can disrupt equilibrium temporarily, but the system counteracts to restore balance, showcasing the dynamic nature of chemical reactions.

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  • What is chemical equilibrium?

    Chemical equilibrium is achieved when the rate of forward and backward reactions are equal, leading to constant properties like pressure, concentration, and density.

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Summary

00:00

Chemical and Ionic Equilibrium Session Details

  • The session is focused on completing both chemical and ionic equilibrium.
  • The class is expected to last 3.5 to 4 hours, ending around 8:00.
  • The teacher encourages students to assist each other in the chat box for doubt resolution.
  • The teacher announces upcoming visits of other teachers to various cities.
  • Details about Vedantu Learning Centers and their programs are shared.
  • The teacher explains the concepts of static and dynamic equilibrium using practical examples.
  • Different types of reactions are classified based on physical state into homogeneous and heterogeneous reactions.
  • Homogeneous reactions involve all reactants and products in the same phase.
  • Heterogeneous reactions have reactants and products in different phases.
  • Reversible reactions involve products converting back to reactants and vice versa.

14:38

Chemical Reactions: Equilibrium, Exothermic, Endothermic, and More

  • Reversible reactions move in both forward and backward directions, indicating a bidirectional process.
  • Equilibrium is achieved in reversible reactions, where products can convert back to reactants.
  • Irreversible reactions, like zinc reacting with sulfuric acid, only proceed in the forward direction.
  • Fast reactions are typically ionic, such as hydrochloric acid reacting with sodium hydroxide to form NAC and H2O.
  • Slow reactions are molecular, like H2 combining with I2 to form 2 moles of HI.
  • Exothermic reactions release heat, like the reaction between hydrochloric acid and sodium hydroxide.
  • Endothermic reactions absorb heat, such as in cooking processes.
  • Dynamic equilibrium in chemical reactions involves the rate of forward and backward reactions being equal.
  • Physical equilibrium does not alter the chemical properties of substances, like solid to liquid transitions.
  • Dissolution of gases in liquids, as seen in carbon dioxide in soda, follows Henry's Law, where gas mass dissolved is proportional to pressure.

30:09

Understanding Equilibrium: Gas, Physical, Chemical, Dynamic

  • The solubility of gas decreases as per Henry's Law, represented by p = KH * C.
  • Physical equilibrium occurs only in closed systems at a specific temperature.
  • Measurable properties like pressure, volume, and temperature remain constant in physical equilibrium.
  • Dynamic equilibrium is stable, with all opposing forces in balance.
  • Chemical equilibrium involves reversible reactions and is impossible for irreversible reactions.
  • Equilibrium is achieved when the rate of forward and backward reactions are equal.
  • Properties like pressure, concentration, and density remain constant at equilibrium.
  • Catalysts can alter reaction rates but not equilibrium.
  • Equilibrium shifts with temperature changes, leading to a new equilibrium state.
  • Concentrations of reactants and products become constant at equilibrium, depicted in a graph.

46:11

Understanding Equilibrium in Chemical Reactions

  • Equilibrium is not only with molecular reactions but also with coordinate complexes, like NH4Cl forming NH4+ and Cl-.
  • Types of reactions studied include static and dynamic equilibrium, physical and chemical equilibrium.
  • Haber's process involves the formation of ammonia from nitrogen and hydrogen, with concentrations reaching equilibrium.
  • Haber conducted experiments with deuterium, finding similar reactions but with different products.
  • Rate of reaction is defined as the change in concentration per unit time, becoming zero at equilibrium.
  • Law of mass action states that the rate of a chemical reaction is proportional to the product of molar concentrations raised to the power of stoichiometric coefficients.
  • Rate of forward and backward reactions in a reaction like hydrogen and iodine forming H2I2 are proportional to the concentrations of reactants.
  • Law of chemical equilibrium involves equilibrium constant (KC) being the product of products raised to their coefficients divided by reactants raised to their coefficients.
  • Steps to write equilibrium constant include writing the chemical equation, products in the numerator, reactants in the denominator, and raising concentrations to their coefficients.
  • Equilibrium constants have specific characteristics and different types, like KC for concentrations and KP for partial pressures.

01:04:18

Understanding Equilibrium Constants in Chemical Reactions

  • Equilibrium constant (KC) is applicable only at equilibrium state and is independent of initial concentration.
  • KC has definite values for every chemical reaction at a particular temperature.
  • Equilibrium constant value is independent of the Catalyst.
  • Different reactions have different units for equilibrium constant.
  • KC depends on the number of moles or stoichiometric coefficient of the reaction.
  • If the number of moles of product equals the number of moles of reactant, KC has no unit.
  • Resultant equilibrium constant is the product of individual equilibrium constants.
  • Different types of equilibrium constants include KC for molar concentration, KP for partial pressure, and KX for mole fraction.
  • KQ represents the general equilibrium conditions including all species in equilibrium.
  • Factors that do not influence equilibrium constant include concentration changes, pressure and volume alterations, presence of a catalyst, and addition of inert gas at constant pressure and volume.

01:21:22

Equilibrium Constant Influencing Factors and Applications

  • Factors influencing equilibrium constant:
  • Mode of representing a chemical reaction affects equilibrium constant.
  • Stochiometry of the reaction can change equilibrium constant.
  • Temperature influences equilibrium constant.
  • Example of mode of representing a reaction:
  • Changing the representation alters the equilibrium constant.
  • Stochiometric coefficients impact equilibrium constant.
  • Effects of temperature on equilibrium constant:
  • Increasing temperature favors endothermic reactions.
  • Decreasing temperature favors exothermic reactions.
  • Applications of equilibrium constant:
  • Predicts reaction extent based on magnitude.
  • Predicts reaction direction using reaction quotient.
  • Understanding reaction quotient:
  • Similar to equilibrium constant but measured during reaction.
  • Comparing reaction quotient to equilibrium constant predicts reaction direction.
  • Relationship between Gibbs free energy and equilibrium constant:
  • Delta G equals -RT Ln of K or -2.303 RT log of K.
  • Equilibrium constant can be KC or KP based on concentration or pressure.
  • Formulas for Delta G:
  • Delta G equals -RT Ln of K or -Delta G / RT for equilibrium constant calculations.
  • Anti-log calculation for equilibrium constant determination.

01:40:23

Equilibrium, Spontaneous Reactions, and External Stress

  • In electrochemistry, a spontaneous reaction occurs when Delta G is zero, Delta G divided by RT is greater than zero, and K is also greater than zero.
  • A spontaneous reaction proceeds in the forward direction, forming products spontaneously without requiring additional energy.
  • In contrast, a nonspontaneous reaction has Delta G greater than zero, Delta G divided by RT is less than zero, and K is also less than zero.
  • A nonspontaneous reaction proceeds to a small extent towards the products, with the concentration of the products being minimal.
  • External stress applied to a system in equilibrium disturbs the equilibrium temporarily, but the system counteracts the change to restore equilibrium.
  • Stress in a reaction can result from changes in concentration, pressure, volume, temperature, or the addition of an inert gas.
  • Increasing the concentration of reactants favors the formation of products, while increasing the concentration of products favors the reverse reaction.
  • Changing pressure affects equilibrium by shifting towards the side with fewer gaseous moles to adjust to the pressure change.
  • If the number of moles of gas remains the same on both sides of the reaction, a pressure change will not impact the equilibrium.
  • Doubling the pressure in a reaction with different moles of gas on each side will cause the equilibrium to shift towards the side with fewer moles to balance the pressure change.

01:56:16

Chemical reactions, temperature, pressure, catalysts, equilibrium.

  • In chemical reactions, pressure moves from higher to lower pressure areas, following Le Chatelier's principle.
  • Foundation classes are crucial as they establish fundamental concepts that remain relevant in advanced studies.
  • Temperature changes affect reactions; increasing temperature favors the direction that absorbs heat.
  • Endothermic reactions benefit from higher temperatures, promoting the forward reaction, akin to cooking.
  • Exothermic reactions prefer lower temperatures, promoting the reverse reaction to release heat.
  • Adding an inert gas affects equilibrium based on whether volume is constant or allowed to change.
  • Catalysts enhance reaction rates by providing a lower energy pathway, accelerating the process.
  • Degree of dissociation measures the fraction of a substance dissociating into products at equilibrium.
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