reduction and oxidation Flashcards
What is oxidation?
Oxidation is any reaction in which a substance gains oxygen.
Oxidation often involves the reaction of metals with oxygen, such as iron rusting.
What is reduction?
Reduction is a reaction in which a substance loses oxygen.
Reduction is the opposite of oxidation.
What is a redox reaction?
A redox reaction is a reaction in which oxidation and reduction occur simultaneously.
Oxidation cannot occur without reduction happening at the same time.
In the displacement reaction Zn + CuO → ZnO + Cu, which substance is the oxidising agent?
Copper(II) oxide (CuO) is the oxidising agent.
The oxidising agent supplies the oxygen.
In the same displacement reaction, which substance is the reducing agent?
Zinc (Zn) is the reducing agent.
The reducing agent removes the oxygen.
What are spectator ions?
Spectator ions are ions that appear unchanged on both sides of a chemical equation and do not participate in the reaction.
In the equation Mg (s) + Cu2+ (aq) + SO42- (aq) → Mg2+ (aq) + SO42- (aq) + Cu (s), SO42- are spectator ions.
What does the balanced ionic equation for magnesium and copper sulfate illustrate?
It illustrates the transfer of electrons in a redox reaction.
The ionic equation is Mg (s) + Cu2+ (aq) → Mg2+ (aq) + Cu (s).
What happens to magnesium in the reaction with copper sulfate?
Magnesium is oxidised as it loses electrons.
The half equation for this process is Mg → Mg2+ + 2e–.
What happens to copper ions in the reaction with magnesium?
Copper ions (Cu2+) are reduced as they gain electrons.
The half equation for this process is Cu2+ + 2e– → Cu.
What is the definition of an oxidising agent in terms of electrons?
An oxidising agent will oxidise other species in a reaction and is itself reduced, thus gaining electrons.
For example, in the reaction where Fe is oxidised, Cu2+ is the oxidising agent.
True or False: Oxidation is the gain of electrons.
False. Oxidation is the loss of electrons.
Fill in the blank: Reduction is the _______ of electrons.
gain
