1. Endothermic and exothermic reactions
EL: To investigate temperature changes that occur during a chemical reaction
Focus: Endo and Exothermic reactions

2. Menu Exothermic and endothermic reactions.
Experiments: sugar snake, Potato and Liver investigation or Chemical reactions in a Bag
Where does the heat energy come from?

3. Exo and endothermic reactions
Exothermic reactions release heat energy to the surroundings.
Can you think of an example?
Endothermic reactions absorb heat energy from the surroundings.

4. Explosions
This reaction is exothermic!

5. Photosyntesis
This reaction is endothermic!

6. Combustions
These reactions are exothermic!

7. Cold and hot packs
How do instant hot and cold packs work?

8. Hot pack Pressing the bottom , the diaphragm breaks.
Calcium chloride dissolves in water and warms it.
The beverage gets warm.

9. Exothermic process
Heat flows into the surroundings from the system in an exothermic process.
Energy
Surroundings
Hot pack
Temperature rises

10. Sugar snake

11. Cold pack
Water and ammonium nitrate are kept in separate compartments.
Pressing the wrapper, the ammonium nitrate dissolves in water and absorbs heat.
The pack becomes cold.
It is used to treat
sports injuries.

12. Endothermic process
Heat flows into the system from the surroundings in an endothermic process.
Surroundings
Cold pack
Energy
Temperature falls

13. Where does the heat energy come from?
In groups of 3-4 people, each student is given a cut up slips of paper with theory about chemical energy
each student must read out their information to the group,
once everyone has read their information out, the group students place the slips in correct order then the group re- reads all the theory together.

14. Investigation Choose to complete either the:
Potato and Liver investigation (this a student designed experiment longer experiment) or
Chemical reactions in a Bag

15. Reflection
Update your concept map with what you learnt about endo and exothermic reactions today
What exothermic reactions or endothermic reactions do you know?