How to Use This Worksheet Work in order. Section A checks the ideas: the steady state, when the pre-equilibrium approximation applies, equilibrium constant expressions, and the effective constant k’. Section B practises the working skills: substitution, denominator rate laws, numerical effective constants, and a steady state with no equilibrium. Section C combines everything in exam … Read more
An Intermediate in a Steady State An intermediate is formed in one step of a mechanism and consumed in a later step (Topic 5.7). It is never poured into the vessel and never collected at the end. After a very short opening period, an intermediate is consumed almost as fast as it is formed. Its … Read more
Master AP Chemistry Topic 5.9 with this free practice quiz. Test your skills on the steady-state approximation, solving for intermediates, and checking mechanisms against experimental rate laws to prepare for your AP exam. An Intermediate in a Steady State An intermediate is formed in one step of a mechanism and consumed in a later step … Read more
14 exam-style problems on slow steps, pre-equilibrium and fractional orders, plus judging mechanisms against experimental rate laws, with full worked answers.
Rate law from a mechanism: find the slow step, remove intermediates through fast equilibria, and judge each proposal against the experimental rate law.
Master AP Chemistry Topic 5.8 with this free practice quiz. Test your skills on rate determining step, mechanism validity, and predicting rate laws to prepare for your AP exam. The Rate-Determining Step The steps of a mechanism (Topic 5.7) do not all run at the same speed. The slowest step is the bottleneck: nothing later … Read more
How to Use This Worksheet Work in order. Section A checks the vocabulary: mechanism, elementary step, intermediate, catalyst, transition state, and the two tests a proposed mechanism must pass. Section B practises the working skills: adding steps, cancelling species, spotting the step that must be multiplied, judging proposals. Section C combines everything in exam style, … Read more
A Mechanism Is a Sequence of Elementary Steps The overall equation of a reaction shows only the net change: which species are consumed and which are produced. It says nothing about the route between the two. A reaction mechanism is the sequence of elementary steps by which the reaction actually happens. Each step is one … Read more
How to Use This Worksheet Work in order. Section A checks the vocabulary of the diagram: axes, peaks, valleys, and what each difference between levels means. Section B practises the arithmetic on described profiles: activation energies in both directions, ΔH, a catalysed curve, and a two-peak profile. Section C combines the ideas in exam style. … Read more
The Reaction Coordinate Diagram A reaction energy profile plots potential energy on the vertical axis, in kJ/mol, against reaction progress on the horizontal axis, the reaction coordinate. The horizontal axis is not time: it tracks how far the rearrangement of atoms has advanced. The curve begins on a flat level at the energy of the … Read more