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

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

Combined science

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

Physical activity and equipment requiring safe use

an X placed under the reaction mixture is no longer visible

In the disappearing cross experiment, which of the following indicates the end point of the reaction?

the reaction mixture changes from clear to cloudy

Which of the following is observed when sodium thiosulfate reacts with hydrochloric acid?

When sodium thiosulfate and hydrochloric acid react together, a yellow precipitate of sulfur forms. In which state is this sulfur?

Increasing the concentration of reactants introduces more...

a higher concentration produces a larger amount of product

a lower concentration produces a larger amount of product

the different concentrations produce different products

the different concentrations produce the same amount of product

Which statement about the amount of product formed at the end point of the disappearing cross experiment, when using different concentrations of sodium thiosulfate in excess, is correct?

all the reactants have been converted to products.

some of the reactants have not yet reacted.

At the end point of a reaction, the reaction may not be complete because ...

Concentration and rate of reaction are directly proportional.

Concentration and rate of reaction are inversely proportional.

Concentration has no effect on the rate of reaction.

Only high concentrations affect the rate of reaction.

Which of the following statements about concentration and rate of reaction is correct?

Doubling the concentration of a reacting solution doubles the rate of reaction.

Doubling the concentration of a reacting solution halves the rate of reaction.

Halving the concentration of a reacting solution doubles the rate of reaction.

Halving the concentration of a reacting solution halves the rate of reaction.

What effect does concentration have on the rate of reaction?

Which of the following methods is used when we measure the progress of a reaction until it has reached a desired point?

Which variable is the independent variable in an experiment where we change the concentration and measure the time taken for a colour change to occur?

Which variable is the dependent variable in an experiment where we change the concentration and measure the time taken for a colour change to occur?

What is the main reason for repeating a rate of reaction experiment multiple times?

Content guidance

Risk assessment required - equipment

Adult supervision required

Introduction

What will you need for this lesson?

Are you ready to learn?

Equipment

Content guidance

Supervision

Worksheet