Chapter 6 Oxidation and Reduction Flashcards
What is a redox reaction?
-A redox reaction is a chemical reaction involving the transfer of electrons between species.
-One substance is oxidised (loses electrons) and another is reduced (gains electrons)
What happens to the oxidation number in oxidation and reduction?
In oxidation, the oxidation number increases.
In reduction, the oxidation number decreases
How do you identify a redox reaction?
By looking for changes in oxidation numbers of species involved in the reaction
What is an oxidation half-equation and which side are the electrons on?
An equation that shows the species losing electrons.
Electrons are on the right side.
What is a reduction half-equation and which side are the electrons on?
A equation that shows the species gaining electrons. Electrons are on the left side
How are redox equations balanced using half-equations?
-Write separate half equations
-Equalise electrons
-Add the equations
-Cancel out species occurring on both sides
Why is an acidic medium often used in redox reactions involving polyatomic ions?
Because H+ ions are needed to balance the reaction, and acids like H2SO4 provide these ions without being oxidised to reduced
What are oxidation numbers of an atom?
It is the charge that atom would have if the compound was composed of ions
What does a positive oxidation number mean?
The atom loses electrons
What does a negative oxidation number mean?
The atom gains electrons
A oxidation number of 0 means..?
The atom neither gains nor loses electrons.
What is an acronym that can be used to remember what happens to electrons during redox?
OIL RIG
-OIL: Oxidation is loss of electrons
-RIG: Reduction is gain of electrons
When does a metal displacement reaction occur?
It occurs when a solid metal is added to an ionic metal solution
What is the general equation for metal displace reaction
AB(aq)
