Exthotermic and Endothermic

1. Exothermic and Endothermic Reactions
Learning Intentions;
1. To define the terms endothermic and exothermic in relation to reactions.
2. To interpret experimental data with respect to endothermic and exothermic
reactions.
3. To describe examples of endothermic and exothermic reactions.
Starter- Think, Pair, Share;
What do you think the words
Exothermic and Endothermic
mean? Use the visual clues.
EXO
ENDO
Thermic

2. Key Definitions;
An exothermic reaction is one that transfers energy to
the surroundings e.g. combustion
An endothermic reaction is one that takes in energy
from the surroundings e.g. thermal decomposition
Question;
Why do you think that the words are colour coded?

3. Practical;
Reaction Temperature
before
mixing/oC
Temperature
after
mixing/oC
Endothermic
or
exothermic?
Sodium
hydroxide
solution +
dilute
hydrochloric
acid
Sodium
hydrogen
carbonate
solution +
citric acid
Safety;
1.Eye protection must be
worn
2.Hold the plastic cup
when the thermometer
is placed in it to prevent
spillages.
Instructions;
1. Measure out 10ml of the
first chemical and place it
into the cup.
2. Take the start temperature
and note it in your table.
3. Add 10 ml (or 2 spatulas) of
the second chemical and
stir.
4. Note the temperature.
Attempt the Super Challenge!

4. 1.
Heat is given out in a
combustion reaction
A fuel and oxygen
are combined to
produce carbon
dioxide and water

5. 2.
These food cans self-
heat the food that they
contain. They transfer
heat energy to the food to
ensure that it is hot for
people to eat.

6. 3.
In order to make ice
cubes, water has to be
cooled, energy is
taken away from it.

7. Reaction Exo or
Endo?
Reason
1.
2.
3.
Reaction Exo or
Endo?
Reason
1.
2.
3.

8. Exam Style Question
Show me Your Lights;
Red = I would struggle to identify
exothermic and endothermic
reactions from experimental data
Amber = I would be able to identify
exothermic and endothermic
reactions from experimental data
with a little assistance
Green = I am an expert!

9. Amber Assistance;
■ What is the purpose of a sports injury
pack? Is it made to cool you down or
heat your injury up?
■ What does the temperature change tell
you?

10. Dedicated Improvement Time;
■ Have you explained your choices in the
exam style question? How do you know
if they are endo or exo?
■ Have you attempted the super
challenge?
■ Why must self-heating food cans
represent an exothermic reaction?

11. Exothermic or Endothermic?
Stand up= Exothermic
Sit Down = Endothermic
■Combustion
■Neutralisation (Hint; look at the first
example in your table)
■Self-heating food can
■Sports injury pack