Reaction rates and mechanisms
What students will learn
Use controlled rate evidence to test proposed molecular pathways, keeping concentration sensitivity, barriers and thermodynamic favorability distinct.
Before this topic
- Balanced reactions, molarity and slopes
- Bond rearrangement and energy profiles
- Logarithms and reciprocal graphs
Read and connect
Read: Reaction Rates →
Name the species and distinguish its disappearance rate from a stoichiometrically normalized reaction rate.
Read: Introduction to Rate Law →
Infer empirical orders from controlled initial-rate comparisons and check rate-constant units.
Read: Concentration Changes Over Time →
Choose concentration, logarithmic or reciprocal graphs and interpret model limits and half-life.
Read: Elementary Reactions →
Infer a step’s rate law from molecularity only when the event is explicitly elementary.
Read: Collision Model →
Explain energy-tail area and encounter orientation with normalized collision models.
Read: Reaction Energy Profile →
Read forward and reverse barriers separately from endpoint energy change; the coordinate is not time.
Read: Introduction to Reaction Mechanisms →
Sum a balanced mechanism and distinguish intermediate, catalyst and transition state.
Read: Reaction Mechanism and Rate Law →
Test slow-first-step predictions against observed rate laws under stated supply conditions.
Read: Pre-Equilibrium Approximation →
Use rapid forward/reverse rate balance to eliminate an intermediate before predicting a net rate law.
Read: Multistep Reaction Energy Profile →
Measure each local multistep barrier from its starting valley rather than an arbitrary zero.
Read: Catalysis →
Explain complete regenerated catalytic cycles and why a changed path leaves the endpoint enthalpy unchanged.
Supporting reading: Kinetic Molecular Theory →
Revisit distribution spread and area before interpreting collision-energy tails.
Supporting reading: Thermodynamic and Kinetic Control →
Later contrast: explain a favorable but slow change using separate free-energy and activation-barrier arrows.
Before this connection: Entropy, free energy, and chemical change: standard free energy; Chemical equilibrium.
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.
Infer and test a rate law →
Use controlled trial ratios, determine k with units and make an independent rate prediction.
Test whether rate orders identify a unique mechanism →
Derive two matching predicted laws and explain what additional supplied evidence would distinguish the mechanisms.
Explain two complete catalytic routes →
Identify protonated and surface-bound intermediates, show catalyst restoration and justify the unchanged net enthalpy.
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.