Reagents and Equipment
6 slices (fresh or pre-diced) of a fruit or vegetable that browns when exposed to air, such as an apple or a potato, of the same size, several food containers, water, cooking oil, refrigerator.
Procedure
1. Place
Slice 1 (nothing else) in a container at room temperature.
Slice 2, covered with water, in another container at room temperature.
Slice 3, coated with cooking oil, in another container at room temperature.
Compare Slices 1, 2 and 3 approximately every half an hour until at least one of them browns. (No longer than 3 hours total.) Record your observations.
2. Place
Slice 4 (nothing else) in a container in the refrigerator.
Slice 5, covered with water, in another container in the refrigerator.
Slice 6, coated with cooking oil, in another container in the refrigerator.
Compare Slices 4, 5 and 6 approximately every hour until at least one of them browns. (No longer than 3 hours total.) Record your observations.
Report Requirements
1. Watch the videos linked below and read the corresponding pages in your lecture textbook:
Applications: Reaction Conditions Affect Reaction Products: https://www.youtube.com/watch?v=mAqJmEjCy4E
Oxidation-Reduction Reactions: YouTube Professor Dave Explains Oxidation and Reduction
https://www.youtube.com/watch?v=VXvtkwubQQg
Organic Oxidation and Reduction: YouTube Professor Dave Organic Oxidation and Reduction
2. Browning of fruits and vegetables is a sign of an oxidation reaction. In your experiment, did oxidation happen faster at room temperature (Slices 1 – _3) or in the refrigerator (Slices 4 – _6)?
3. In your experiment, did oxidation happen faster with uncovered slices (Slices 1 and 4), slices in water (Slices 2 and 5), or slices in cooking oil (3 and 6)?
4. Based on your experiment, which would be the best method to preserve pre-sliced fruits or vegetables from oxidizing?
5. If no oxidation was observed after 3 hours for any of the slices, what may be the reasons?
6. In your own words, what is oxidation?