Rate of reaction is the speed with which a chemical reaction takes place.

The mean rate of reaction is the average rate at which reactants are converted into products over a given period of time.

The instantaneous rate of reaction is the rate at which reactants are converted into products at a specific moment in time.

A tangent is a straight line that touches a curve at exactly one point without crossing it.

The gradient on a graph represents the rate at which one quantity changes relative to another.

The rate of a chemical reaction: including graphs

Chemistry

In the Industrial Chemistry unit, pupils will build on their knowledge of reaction rates to learn about the industrial processes involving chemical reactions and the factors that affect them.

In the Energy Changes in Reactions unit, pupils learned about bond breaking, bond making, and reaction profiles.

This unit explores factors influencing reaction rates, including temperature, concentration, surface area, and catalysts. It covers using models and theories to develop hypotheses, planning and conducting experiments safely, selecting appropriate techniques, and presenting and translating data.

Rate of reaction

Rate of reaction is the speed with which a chemical reaction takes place, measured by the amount of a reactant used or amount of product formed in a given time.

Volume is how much 3D space matter occupies. It is usually measured in cm³.

Accurate measurements are those that are close to the true value.

Precise measurements have very little spread from the mean value. They are values that lie close to each other.

Appropriate equipment for measuring the rate of a reaction

The collision theory is that particles must collide, and with sufficient energy, in order to react.

The minimum energy that the particles must have in order to react is known as the activation energy.

Collision theory

The surface area to volume ratio is the surface area of a solid relative to its volume.

The independent variable is the single variable that is changed in an investigation.

The dependent variable is the single variable that is measured or observed in an investigation.

The control variables are variables that are kept constant in an investigation.

Surface area and rate: practical

The mean rate of reaction is the average rate at which reactants are converted into products in a given time.

Surface area and rate: analysis

Concentration and rate: practical using gas collection method

An end point method is used to measure the progress of a reaction until it has reached completion or a desired point e.g. a colour change.

A precipitate is an insoluble solid formed when two solutions react together.

In a fair test variables are controlled so that only one change affects the dependent variable.

Concentration and rate: practical using end point method

A reactant in excess is present in a greater amount than is necessary to completely react with the limiting reactant.

Concentration and rate: analysis

An end-point method is used to measure the progress of a reaction until it has reached completion or a desirable point, e.g. a colour change.

Temperature and rate: practical

Accuracy refers to how close a measured value is to the true or standard value.

A method is described as repeatable if a person uses the same method and obtains the same/similar results when repeating the experiment.

A parallax error occurs when a measurement is not taken at eye-level.

A systematic error is caused by the equipment used.

Evaluating methods for measuring the rate of reaction

A catalyst is a chemical that increases the rate of a reaction without itself being used up.

Reaction profiles are diagrams that show the energy of the reactants and products in a chemical reaction.

Qualitative data is information that describes qualities or characteristics that cannot be measured with numbers.

Rate of reaction

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These lessons will be removed by end of Summer Term 2025.