Chemical equilibrium
What students will learn
Use dynamic particle reasoning and Q/K bookkeeping to predict equilibrium composition, disturbances and dissolution without confusing amount with rate.
Before this topic
- Reacting proportions and solution concentration
- Forward and reverse rates
- Energy-transfer signs and particle models
Read and connect
Read: Introduction to Equilibrium →
Distinguish constant unequal concentrations from equal nonzero forward and reverse rates.
Read: Direction of Reversible Reactions →
Use simultaneous forward/reverse events and stoichiometry to explain net direction.
Read: Reaction Quotient and Equilibrium Constant →
Write Q and K for the stated species and phases; pure solids are conditions, not variable terms.
Read: Calculating the Equilibrium Constant →
Infer K from equilibrium measurements after converting amounts to concentrations or partial pressures.
Read: Magnitude of the Equilibrium Constant →
Interpret K for the exact equation without treating it as a speed or unqualified percentage.
Read: Properties of the Equilibrium Constant →
Reverse, scale and add equations while transforming their quotients and equilibrium constants consistently.
Read: Calculating Equilibrium Concentrations →
Choose net progress from Q/K and solve checked equilibrium concentration changes.
Read: Representations of Equilibrium →
Construct a scaled equilibrium particle representation with atom conservation and ongoing opposite events.
Read: Introduction to Le Châtelier’s Principle →
Separate the immediate physical disturbance from the subsequent net reaction and measurement response.
Read: Reaction Quotient and Le Châtelier’s Principle →
Use quotient algebra to justify a disturbance’s direction; temperature can also change K.
Read: Introduction to Solubility Equilibria →
Build dissolution expressions, distinguish ion concentration from salt solubility, and use post-mixing Qsp.
Read: Common-Ion Effect →
Include every common-ion source and verify any negligible-change approximation.
Supporting reading: Pre-Equilibrium Approximation →
Connect reversible rate balance to the pre-equilibrium approximation used inside a mechanism.
Supporting reading: pH and Solubility →
Later coupled-equilibrium connection: proton transfer changes the free-ion product and total dissolved material.
Before this connection: Acids, bases, and pH: conjugate pairs and proton-transfer equilibria.
Supporting reading: Free Energy and Equilibrium →
Later free-energy connection: distinguish standard-state preference from the current mixture’s Q.
Before this connection: Energy transfer and enthalpy; Entropy and standard free energy.
Check understanding
Use the complete prompt to make student reasoning visible, then consult the separate worked reasoning and criteria. A reading completion tick records reading history.
Calculate and check an equilibrium composition →
Use initial Q to choose direction, solve balanced changes and verify nonnegative values, total amount and Q = K.
Construct a later equilibrium snapshot →
Create a same-scale particle model with forward/reverse event arrows and explain average composition and small-picture limits.
Compare dissolution with a common-ion control →
Include the added ion source, check the approximation and predict a changed concentration without changing fixed-temperature Ksp.
Standards and earlier reading lists
These topic placements organize reading. Edition-qualified Standards mappings and the existing complete unit task sets retain their reviewed scope.