Redox Reactions Flashcards
What is oxidation?
- The loss of electrons
- Gain of oxygen (or any electronegative element)
- Loss of hydrogen ( or any electropositive element)
What is reduction?
- The gain of electrons
- loss of oxygen (or any electronegative element)
- Gain of hydrogen (or any electropositive element)
What is an oxidizing agent?
a species that gains electrons
What is a reducing agent?
Species that lose electrons.
What are the half equations and the ionic equation for:
SnO + Zn => ZnO + Sn
Half equations:
1. Sn2+ + 2 e- => Sn
2. Zn => Zn2+ + 2e-
Ionic equation:
Sn2+ + Zn => Sn + Zn2+
Define oxidation state.
A number which represents the number of electrons lost or gained by an atom of that element in the compound.
(if electrons are lost number is positive, if electrons are gained. Number is negative)
What is the oxidation state of oxygen in OF2?
[O] = +2
(otherwise [O] = -2 in most other compounds)
What is the oxidation state of hydrogen in KH?
[H] = -1
( [H] = -1 for metal hydrides. Otherwise [H] = +1 in most other compounds)
What is the oxidation state of chlorine in NaClO?
[Cl] = +1
(Otherwise [Cl] = -1 in most other compounds. NaClO is formed in a disproportionation reaction.)
Define the term disproportionation?
Where in a redox reaction, the oxidation states of atoms of the same element, increase for some atoms, where decrease for some atoms.
( e.g. See topic 2.3 - Group 7(17), the halogens for example in Uses of Chlorine)
What is the oxidation state of phosphorus in PCl5?
[P] = +5
What is the oxidation state of nitrogen in ammonia?
[N] = -3
What is the oxidation state of arsenic in AsO4 3-?
[As] = +5
What is the oxidation state of iron in K4 Fe (CN)6?
[Fe] = +2
Why is 1s2 2s2 2p5 a weaker reducing agent than 1s2 2s2 2p6 3s2 3p6 4s2?
The 2p electron is closer to the nucleus thus smaller atom than the 4s electron. Hence the nuclear attraction is stronger so the 2p electron is lost less easily than the 4s electron.
