⚖️ Kinetics & Equilibrium
91 chemistry topics in Kinetics & Equilibrium, from beginner to intermediate to advanced level. Each topic has a clear explanation, a worked example, frequently asked questions and an interactive lesson.
Beginner topics in Kinetics & Equilibrium (11)
- Chemical KineticsThe study of reaction rates and the steps by which reactions occur.
- Reaction RateThe change in concentration of a reactant or product per unit time.
- Temperature Effect on RateA rise of about 10 degrees often doubles reaction rate because more molecules exceed…
- Effect of Concentration on RateHigher concentrations give more frequent collisions and faster reaction rates.
- Effect of Surface AreaFinely divided solids react faster because more surface is exposed.
- CatalystA substance that speeds up a reaction by providing a lower-energy path without being…
- Reversible ReactionsReactions that can proceed in both directions toward an equilibrium.
- Dynamic EquilibriumThe state in which forward and reverse reaction rates are equal and concentrations remain…
- Le Chatelier's PrincipleA system at equilibrium shifts to counteract any imposed change in conditions.
- Effect of Concentration on EquilibriumAdding reactant shifts equilibrium to products; removing product has the same effect.
- Rate vs Time GraphsConcentration-time graphs show how reactants fall and products rise, with slope giving…
Intermediate topics in Kinetics & Equilibrium (46)
- Average and Instantaneous RateAverage rate spans a time interval; instantaneous rate is the slope of the concentration…
- Rate LawAn equation relating rate to concentrations raised to experimentally determined powers.
- Rate ConstantThe proportionality constant k in the rate law, depending on temperature and catalyst.
- Order of ReactionThe sum of exponents in the rate law, determined experimentally not from stoichiometry.
- Zero Order ReactionRate is independent of concentration, and concentration falls linearly with time.
- First Order ReactionRate is proportional to one concentration; ln of concentration falls linearly with time.
- Second Order ReactionRate depends on the square of concentration, with 1 over concentration rising linearly in…
- Half-life of ReactionsFirst-order half-life equals 0.693 over k and is independent of initial concentration.
- Method of Initial RatesFinding reaction orders by comparing initial rates across experiments with different…
- Integrated Rate LawsEquations giving concentration as a function of time for each reaction order.
- MolecularityThe number of species colliding in an elementary step.
- Elementary ReactionsSingle-step processes for which the rate law follows directly from stoichiometry.
- Reaction MechanismThe sequence of elementary steps that make up an overall reaction.
- Rate-Determining StepThe slowest step in a mechanism that limits the overall rate.
- Reaction IntermediateA species formed in one step and consumed in a later step, not appearing in the overall…
- Collision TheoryReactions occur when particles collide with sufficient energy and proper orientation.
- Activation EnergyThe minimum energy colliding molecules need for reaction.
- Arrhenius Equationk equals A times e to the minus Ea over RT, linking rate constant to temperature.
- Homogeneous CatalysisThe catalyst and reactants are in the same phase.
- Heterogeneous CatalysisThe catalyst is in a different phase, typically a solid surface with gaseous reactants.
- Enzyme CatalysisBiological catalysts accelerating reactions with high specificity by binding substrates…
- Photochemical ReactionsReactions initiated by light absorption, such as photosynthesis and ozone formation.
- Equilibrium ConstantThe ratio of product to reactant concentrations raised to stoichiometric powers at…
- Kc and KpEquilibrium constants in terms of concentration and partial pressure, related by Kp…
- Reaction QuotientThe same expression as K evaluated at any moment; comparing Q with K indicates the…
- Magnitude of KLarge K favours products, small K favours reactants.
- Homogeneous and Heterogeneous EquilibriaPure solids and liquids are omitted from the equilibrium expression.
- Manipulating KReversing a reaction inverts K; multiplying coefficients raises K to that power; adding…
- ICE TablesA method tracking initial, change and equilibrium concentrations to solve equilibrium…
- Effect of Pressure on EquilibriumIncreasing pressure shifts equilibrium toward the side with fewer gas moles.
- Effect of Temperature on EquilibriumRaising temperature favours the endothermic direction and changes K.
- Effect of Catalyst on EquilibriumCatalysts speed equilibrium attainment but do not change the position or K.
- Haber ProcessAmmonia synthesis from N2 and H2 over iron catalyst at about 450 degrees and 200 atm…
- Contact ProcessIndustrial production of sulfuric acid via SO2 oxidation over vanadium pentoxide catalyst.
- Solubility ProductKsp is the equilibrium constant for dissolving a sparingly soluble ionic solid.
- Common Ion EffectAdding an ion common to an equilibrium reduces solubility or ionization.
- Precipitation PredictionA precipitate forms when the ion product Q exceeds Ksp.
- Equilibrium in Gas PhasePartial pressures replace concentrations in the equilibrium expression.
- Degree of DissociationThe fraction of a substance that dissociates at equilibrium.
- Clock ReactionsReactions where a sudden color change appears after a measurable delay, such as iodine…
- Catalytic ConvertersPlatinum group metals convert CO, NOx and hydrocarbons in exhaust into CO2, N2 and water.
- Inhibitors and PoisonsSubstances that slow reactions or deactivate catalysts by blocking active sites.
- Reaction Coordinate DiagramA graph showing energy changes along the reaction path with barriers and intermediates.
- Buffer EquilibriaConjugate pairs maintain nearly constant pH by shifting equilibrium after small additions.
- Heterogeneous Equilibrium VaporVapor pressure of a liquid in a closed container reflects dynamic phase equilibrium.
- Equilibrium Constant of WaterKw equals 1.0 x 10^-14 at 25 degrees Celsius for the autoionization of water.
Advanced topics in Kinetics & Equilibrium (34)
- Pseudo First Order ReactionA higher-order reaction behaves as first order when one reactant is in large excess.
- Steady State ApproximationAssumes intermediate concentration remains constant because it forms and reacts at equal…
- Pre-equilibrium ApproximationA fast reversible step treated as equilibrium before a slow rate-determining step.
- Transition State TheoryReactants pass through a high-energy activated complex at the top of the energy barrier.
- Activated ComplexThe unstable arrangement of atoms at the energy maximum between reactants and products.
- Arrhenius PlotA graph of ln k versus 1 over T whose slope is minus Ea over R.
- Pre-exponential FactorThe constant A representing collision frequency and orientation probability.
- Michaelis-Menten KineticsDescribes enzyme rates as a saturating function of substrate concentration using Vmax and…
- Lineweaver-Burk PlotA double reciprocal plot used to determine Vmax and Km of enzymes.
- Enzyme InhibitionCompetitive and noncompetitive inhibitors reduce enzyme activity by different mechanisms.
- AutocatalysisA reaction in which a product acts as a catalyst, giving sigmoidal concentration profiles.
- Chain ReactionsReactions proceeding through initiation, propagation and termination steps involving…
- Oscillating ReactionsReactions such as Belousov-Zhabotinsky show periodic concentration changes.
- Quantum YieldThe number of molecules reacting per photon absorbed.
- Ostwald ProcessNitric acid is made by catalytic oxidation of ammonia on platinum-rhodium gauze.
- Equilibrium and Free EnergyStandard Gibbs energy change equals minus RT ln K.
- Selective PrecipitationIons are separated by adding reagent so that one salt precipitates first.
- Complex Ion EquilibriaFormation constants describe equilibrium of metal ions with ligands.
- Effect of Complexation on SolubilityComplex formation can dissolve otherwise insoluble salts, as AgCl dissolves in ammonia.
- Relationship of Rate Constants and KK equals the ratio of forward to reverse rate constants for an elementary reaction.
- Principle of Microscopic ReversibilityThe mechanism of a forward reaction is the reverse of the backward mechanism at…
- Kinetic vs Thermodynamic ProductAt low temperature the faster-forming product dominates; at high temperature the more…
- Hammond PostulateThe transition state of a step resembles the species nearest it in energy.
- Eyring EquationRelates rate constants to activation enthalpy and entropy via transition state theory.
- Lindemann MechanismExplains unimolecular reaction pressure dependence through collisional activation.
- Diffusion-Controlled ReactionsReactions so fast that rate is limited by how quickly reactants meet.
- Relaxation MethodsTechniques such as temperature jump that perturb equilibrium to measure fast kinetics.
- Flash PhotolysisA short intense light pulse initiates reaction so fast intermediates can be observed.
- Surface Catalysis StepsReactants adsorb, react on the surface, and products desorb in heterogeneous catalysis.
- ZeolitesMicroporous aluminosilicates serving as shape-selective catalysts in petrochemistry.
- Equilibrium in BiologyCellular reactions are held away from equilibrium by continual supply of substrates and…
- Partition CoefficientThe ratio of a solute's concentration in two immiscible solvents at equilibrium.
- Distribution LawAt constant temperature a solute distributes between two solvents in a constant ratio.
- Steady State vs EquilibriumSteady state has constant concentrations from continuous flows, unlike closed-system…
Frequently asked questions about Kinetics & Equilibrium
How many topics are in Kinetics & Equilibrium?
Kinetics & Equilibrium has 91 topics, from beginner to intermediate to advanced level.
Where should I start in Kinetics & Equilibrium?
Start with Chemical Kinetics at the beginner level, then work through the topics in order.
Does every topic have an explanation and an example?
Yes. Each topic page has an in-depth explanation, a worked example, FAQs and links to related topics.