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Reduction-Oxidation
Redox related questions and definitions for AP Chem
Question | Answer |
---|---|
What does redox stand for? Is Oxygen always necessary? | Redox is short for reduction-oxidation. Oxygen does not always have to be involved. |
What happens in a redox reaction? | A transfer of electrions occurs from one substance to another. |
Which type of reaction is never a redox reaction? Is combustion a redox reaction? | Double replacement reactions are never redox. Combustion is a redox reaction because oxygen is a reactant that is reducing, or acting as the oxidation agent. |
What does LEO goes GER mean? | LEO: Loss of electrons is oxidation GER: Gain of electrons is reduction |
What is important to remember when assigning oxidation numbers according to the rules? | The rules are hierarchical, and the rules that apply and appear first are more important and should not be broken. |
Rule 1 The ____ of all the oxidation numbers in a compound must equal ______ | 1. sum 2. zero |
Rule 2 Free elements are _____ | Zero |
Rule 3 Ion charge is the ______ | The oxidation number |
Rule 4 Fluorine has an oxidation number of _____ as well as the other _______, as long as they are at the _____ of the molecule. | 1. -1 2. ealogens 3. end |
Rule 5 Oxygen is usually _____, unless it is combined with fluorine where it is ______ or in peroxides where it is _____. | 1. -2 2. +2 3. -1 |
Rule 6 When hydrogen is a cation its number is ____, and when it is an anion its number is ____. | 1. +1 2. -1 |
Rule 7 The ____ of the oxidation numbers must equal to the ____ of the anion. | 1. sum 2. charge |
Why do we need to assign oxidation numbers? | So we can clearly see which elements are being oxidized and which are being reduced. When the charge increases, it was oxidized. When the charge decreases, it was reduced. |
When assigning oxidation numbers to compounds with polyatomic ions, what must you do? | 1. Remember to distribute the charge to all the atoms 2. Assign numbers to the outside elements first |
Reduction | When a substance gains electrons and the charge decreases |
Oxidation | When a substance loses electrons and the charge increases |
Reducing Agent | An element that makes the other element reduce its charge; the element that is being oxidized. |
Oxidizing Agent | An element that makes the other element increase its charge; the element that is being reduced. |
What is a spectator? | An element that is not reducing or oxidizing. Its charge remains the same consistently. |
What is a half-reaction? | A reaction with oxidation numbers that only shows the redox of a single element rather than the entirety. |