Oxidation- Reduction Reactions Objectives: Define oxidation, reduction, reducing and oxidizing agent Gather and evaluate data in order to determine if an oxidation-reduction reaction as taken place Create a graph of collected data Identify independent and dependent variables Construct a hypothesis Analyze data; prove or disprove hypothesis by using data

Oxidation Involves a loss of Electrons Some books define oxidation as reaction in which a substance gains oxygen or loses hydrogen. It is also defined as “a reaction that removes one or more electrons” You’ve seen rusted iron and burning wood. Each chemical reaction is fueled by oxygen.

Slow Oxidation Slow oxidation: matter links up with oxygen very slowly. There is no flame Heat is given off, but cannot be felt What happens to a potato if cut and left unwrapped? What happens to an apple when it is cut and left expose to air? What does lemon juice do to cut apples? Ex: rusting of iron, the decay of food, the food we eat oxidizes slowly in order to supply us with the energy to live.

Rapid Oxidation Rapid oxidation: oxygen links up with other matter very rapidly. The chemical reaction gives off a flame and a lot of heat. The flame is rapid oxidation Rapid oxidization is the same as “Combustion” : The oxidizing reaction of an organic compound, in which heat is released.

How can oxidation be prevented? To prevent oxidation, you must prevent oxygen from coming into contact with the material People paint their cars to prevent the metal from rusting Food is wrapped in plastic wrap or aluminum foil Stays fresher longer.

Reduction Reduction: chemical change in which electrons are gained, either by the removal of oxygen, the addition of hydrogen, or the addition of electrons. Think about the addition of lemon juice to a cut apple….oxidation is greatly decreased. Lemon juice is an acid How do you know this? You can visually see that the lemon juice creates a barrier between itself and the environment, the browning effects will not occur as quickly.

Redox reactions Oxidation-reduction reactions: any chemical change in which one species loses electrons (oxidized) and another is reduced(gains electrons); also called redox reaction Redox reactions saves lives! Airbags are filled with sodium azide (NaN 3 ) and iron (III) oxide. Upon impact the mixture is automatically ignited. NaN 3 decomposes in a redox reaction to form sodium and nitrogen