MDCAT Chemistry · Chemistry · Reaction kinetics. The idea in plain words, the rules to remember, the mistake to avoid and a worked example, written and checked by Mega Lecture.
The rate of reaction is the change in concentration of a reactant or product per unit time. It is greatest at the start and falls as the reactants are used up. The rate at one instant is the gradient of the tangent to the concentration–time curve.
The rate law shows how the rate depends on concentration. The powers in it are the orders. They are found only by experiment and cannot be read from the balanced equation.
Reactions between ions in solution are very fast because no bonds need to be broken first. Most reactions of covalent molecules are slow or moderate. A rate is followed by measuring any property that changes with concentration.
Students take the orders from the coefficients in the balanced equation. Orders come only from experimental data: compare two experiments in which just one concentration changes.
Answer: k = 0.50 dm6 mol−2 s−1
Type what you are stuck on. The helper finds the explanation, worked examples and the notes to read, free and instant.
← Ionic equilibriaActivation energy and catalysis →Take a MDCAT Chemistry test