Oxidation and Reduction Definitions
An element undergoing _________________ loses electrons and becomes more positive.
Oxidation
What is the first step in determining if something is oxidised or reduced?
Assign oxidation numbers
When an element is reduced it is also the _______________ agent.
oxidising
A __________ reaction is short for an oxidation-reduction reaction.
redox
True or false?
Oxidation state decreases during reduction.
True
In a redox reaction, the total oxidation state of every molecule should add up to _______.
Zero
The _____________ is the substance that is oxidised.
reducing agent
A redox reaction is defined as a reaction in which ____________ are transferred.
electrons
Does this half reaction show oxidation or reduction?
Al → Al3+ + 3e-
Oxidation
Lone elements always have an oxidation state of __________.
Zero
The reducing agent is the element being ______________.
oxidised
A redox reaction can be identified if 1 or more element underwent a change in ________________________.
oxidation state / oxidation number
Does this half reaction show oxidation or reduction?
Cu2+ + 2e- → Cu
Reduction
If an element went from an oxidation state of +7 down to +4 it was ________________.
Reduced
Which species is the reducing agent in the equation?
2H2 + O2 → 2H2O
Hydrogen / H2
Which reaction is an example of an oxidation reduction reaction?
(1) AgNO3 + KI → AgI + KNO3
(2) Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
(3) 2KOH + H2SO4 → K2SO4 + 2H2O
(4) Ba(OH)2 + 2HCl → BaCl2 + 2H2O
2
Write the half reaction for reduction of Zn2+.
Zn2+ + 2e- → Zn
If an element went from an oxidation state of -2 to 0 it was ______________.
Oxidised
Which species is the oxidising agent in the equation?
2Na + FeCl2 --> 2NaCl + Fe
FeCl2
Which balanced equation represents a redox reaction?
(1) AgNO3 + NaCl → AgCl + NaNO3
(2) BaCl2 + K2CO3 → BaCO3 + 2KCl
(3) CuO + CO → Cu + CO2
(4) HCl + KOH → KCl + H2O
3