Key Definitions 5.1.1

k = Ae^-Ea/RT k: rate constant A: pre-exponential factor Ea: activation energy R: gas constant T: temperature

Reaction where an abrupt visible change occurs. Time taken for change to occur is measured and usually indicates formation of a product.

Technique used to measure the amount of light absorbed by a solution, used to determine the rate of reaction.

a graph in which concentration is plotted on the y axis and time on the x axis. The gradient of the line is equal to the rate of reaction.

during a rate experiment, continuous measurements are taken as the reaction progresses. The results can then be plotted on a concentration-time graph

Concentration of a first order reactant is directly proportional to the rate of reaction

the time taken for the concentration of a reactant to half

a number that relates the rate of a reaction to the concentrations of each reactant

the sum of the orders with respect to each reactant.

a constant value that relates the rate of a reaction at a given temperature to the concentrations of the reactants. For a first order reaction, this can be determined using the relationship k = ln 2/half-life

a graph that has concentration plotted on the x axis and rate on the y axis.

the slowest step of a reaction

relates rate to the concentrations of the reactants multiplied by the rate constant. Each concentration is raised to the power of the order with respect to that reactant.

a measure of how quickly a reactant is used up / a product is formed

a step-by-step sequence of the individual reactions that make up the overall reaction

Rate is directly proportional to the square of the concentration

Concentration of reactant won’t impact rate