ChemistryCode 9701
Simple rate equations, orders of reaction and rate constants
What this topic asks you to be able to do
- explain each of these terms and use it: rate equation, rate constant, order of reaction, overall order of reaction, half-life, intermediate and rate-determining step
- understand, and apply, rate equations taking the form rate = k [A]m[B]n (with m and n each being 0, 1 or 2)
- deduce a reaction's order by reading concentration–time graphs, or by using data gathered through the initial rates and half-life methods
- interpret experimental results shown as graphs, including concentration–time and rate–concentration graphs
- work out an initial rate from concentration data
- construct a rate equation
- demonstrate an understanding that a first-order reaction's half-life does not depend on concentration
- apply a first-order reaction's half-life when carrying out calculations
- calculate a rate constant's numerical value, e.g. via: (a) combining the initial rates with the rate equation (b) applying the half-life, t½, and k = 0.693/t½
- where a reaction has several steps: (a) propose a mechanism agreeing with the rate equation and with the overall equation (b) forecast the order arising from a supplied mechanism together with its rate-determining step (c) derive a rate equation from a provided mechanism and its rate-determining step, for a specified reaction (d) spot an intermediate or catalyst in a given mechanism (e) pinpoint the rate-determining step using a rate equation alongside a mechanism provided
- describe in qualitative terms how raising or lowering the temperature alters the rate constant, and therefore the rate of a reaction