Ch. 20. Oxidation-Reduction Reactions. Types of Reactions. There are many different types of reactions: Redox Acid-Base Precipitation. 20.1 Oxidation and Reduction. Oxidation- Reduction Reaction : reaction in which electrons are transferred from one atom to another AKA- Redox Reaction.
The roaring fire shown to the right is an example of the rapid oxidization of the hydrocarbons making up the wood and the reduction of the Oxygen gas from the air.
The, very rusty, Iron hammer is also being oxidized by the Oxygen in the air, but at a much slower rate than the burning wood.
Oxidation numbers are written with the positive or negative sign BEFORE the number. (+ 3, - 2)
Ionic charge is written with the sign AFTER the number. (3+ , 2-)
Removes tarnish from metal objects such as silver.
Hydrogen peroxide is an antiseptic because it oxidizes biomolecules of germs. It also lightens hair because it oxidizes the dark pigment of the hair.
The oxidation number of an uncombined element is zero.
Includes diatomic molecules, subscripts don’t matter.
The oxidation number of a monatomic ion is equal to the charge on the ion.
Oxidation number of Al3+ is +3.
Oxidation number of Ca2+is+2.
The oxidation number of the more electronegative atom in a molecule or complex ion is the same as the charge it would have if it were an ion.
Hydrogen (H) has two possible oxidation numbers:
The oxidation number of fluorine (F) is always -1
Let's start with Carbon Dioxide, CO2.
1. Neutral compound charge = 0
2. Oxygen gets its standard charge of -2 for each oxygen atom.
3. In order to tally to zero, we MUST assign Carbon the oxidation number of +4.
Neutral compound charge = 0
2. Chlorine is the most electronegative element charge of -1 for each Chlorine atom.
3. both Hydrogen atoms are given an oxidation number of +1.
4. In order to tally to zero, we MUST assign Carbon the oxidation number of 0.
-2 for each oxygen atom.