Citric Acid and Sodium Hydrogen
Carbonate
Developing: Students can set up an experiment safely
Secure: Students can carry out and record results from an experiment
Exceeding: Students can recall the symptoms and cure for scurvy
Entrance Activity
Produce a mini mind map of all of
the stuff we have covered thus far
in this topic.
Key Words – Tool Box
Citric acid
Sodium hydrogen carbonate
Scurvy
Exothermic
Endothermic
Task 6- Citric Acid and Sodium
Hydrogen Carbonate
Exo/Endothermic Reactions
Definition
When bonds are made or broken during a chemical reactions heat is
taken in from the surrounding or given out. This is detected as a change
in temperature.
Safety First!
Instructions
Instructions:
1. Place 2 spatulas of solid citric acid into a boiling tube
2. Add 15 cm3 of water to the boiling tube
3. Hold the boiling tube and feel the temperature of the solution
4. Add 2 spatulas of solid sodium hydrogen carbonate
5. Gently stir with a stirring rod to dissolve both solids
6. Feel the temperature of the solution again
7. Record your results.
Why did this happen?
Fluorescein is used to identify if there is damage to the cornea of a person’s eye.
TASK
Copy and complete the eye diagram below (use colours if possible and highlight labels)
Scurvy!
Scurvy was a disease that caused people’s gums to bleed and teeth to fall out and could in
extreme cases lead to death. Citric acid and ascorbic acid are both found in citrus fruit
(lemons, limes and oranges).
TASK
Imagine you have went back in time to 300 years ago. You are a British sailor in the Royal
Navy that is on a ship that has been sailing for three months! Describe what is happening
to you and your ship mates when the dreaded scurvy attacks! Try and explain how you
ended up getting citrus fruit on to the ship and stopped the whole crew from dying!
Citric Acid and Sodium Hydrogen
Carbonate
Developing: Students can set up an experiment safely
Secure: Students can carry out and record results from an experiment
Exceeding: Students can recall the symptoms and cure for scurvy
Entrance Activity
Produce a mini mind map of all of
the stuff we have covered thus far
in this topic.
Key Words – Tool Box
Citric acid
Sodium hydrogen carbonate
Scurvy
Exothermic
Endothermic