KS4 SCIENCE SUCCESS CRITERIA1. Read the notes in your exercises book the night before

each science lesson.

2. Review the topic being studied on BBC Bitesize for 10 minutes the night before each lesson.

3. On Saturday - Use a science text book/ BBC Bitesize and make your own revision cards for the topic being studied.

4. On Sunday – Read and learn the information on each revision card for the topic being studied.

Read the target sheet for the topic.

Required Practical - Distinguish between exothermic and endothermic reactions on the basis of the temperature change of the surroundings.

Required Practical - Evaluate uses and applications of exothermic and endothermic reactions given appropriate information.

Draw simple reaction profiles (energy level diagrams) for exothermic and endothermic reactions showing the relative energies of reactants and products, the activation energy and the overall energy change, with a curved arrow to show the energy as the reaction proceeds.Use reaction profiles to identify reactions as exothermic or endothermic.Explain that the activation energy is the energy needed for a reaction to occur.(HT) Be able to calculate the energy transferred in chemical reactions using bond energies supplied.

What type of reactions do the diagrams represent?DO NOW

CHEMISTRY TOPIC 5 – ENERGY CHANGES

Exothermic & Endothermic Reactions

Learning Objectives

Define exothermic reaction and endothermic

reaction.

Describe what you would observe when hydrochloric acid

reacts with magnesium ribbon.

BRIDGES - Revising

StarterWhat are exothermic and endothermic reactions?

exothermic reactions release energy – they get hot

endothermic reactions absorb energy – they get cold

ex = out (as in ‘exit’)

en = in (as in ‘entrance’)

Most chemical reactions are exothermic.

thermic = relating to heat

Exothermic and endothermic reactions

Starter

Endothermic reactions absorb thermal energy from the surroundings, and so cause a decrease in temperature.

thermal decomposition, e.g. calcium carbonate in a blast furnace

photosynthesis some types of electrolysis sherbet!

Endothermic reactions

What are some examples?

Exothermic reactions release thermal energy (heat) into their surroundings. Exothermic reactions can occur spontaneously and some are explosive.

combustion respiration neutralisation of acids

with alkalis reactions of metals

with acids the Thermit Process.

Exothermic reactions

What are some examples?

Main

anhydrous copper sulfate

hydratedcopper sulfate + water

CuSO4.5H2O CuSO4 5H2O+

endothermic

exothermic

Reversible reactions and energyReversible reactions are exothermic in one direction and endothermic in the other direction. For example:

The amount of energy transferred in each direction is exactly the same.

Main Exothermic reaction: energy transfer

What happens to energy in the reaction between magnesium and hydrochloric acid?

No external heat source is used so the heat released during the reaction must come from the reactants.

During the reaction, chemical energy in the reactants is converted to thermal energy (heat). This causes the temperature of the reaction mixture to rise.

This thermal energy is eventually lost to the surroundings and the temperature of the reaction mixture returns to normal.

Main

Write a definition for:

exothermic reactionendothermic reaction

List two examples of each type of reaction.

Complete all tasks, starting from the red task.

The energy required for the thermal decomposition of 16.8g

of magnesium carbonate is 23.4kJ.

Write a word equation for the reaction.

Write a balanced symbol equation for the reaction,

include state symbols.

Main

Write a definition for:

exothermic reactionendothermic reaction

List two examples of each type of reaction.

Then mark and correct in green pen.

Exothermic reactions release thermal energy (heat) into their surroundings

Endothermic reactions absorb thermal energy from the surroundings, and so cause a decrease in temperature.

combustion respiration neutralisation of

acids with alkalis reactions of

metals with acids the Thermit

Process.

thermal decomposition, e.g. calcium carbonate in a blast furnace

photosynthesis some types of

electrolysis sherbet!

The energy required for the thermal decomposition of 16.8g of magnesium carbonate

is 23.4kJ.Write a word equation for the reaction.

Write a balanced symbol equation for the reaction, include state symbols.

MgCO3(s) → MgO (s) + CO2(g)

magnesium carbonate → magnesium oxide + carbon dioxide

Plenary Complete the exam practise question.

CHEMISTRY TOPIC 5 – ENERGY CHANGES

Lesson 1 – Exothermic & Endothermic Reactions

Learning Objectives

Define exothermic reaction and endothermic

reaction.

Describe what you would observe when hydrochloric acid

reacts with magnesium ribbon.

BRIDGES - Revising