1.7 - Oxidation, Reduction and Redox Reactions Flashcards
What is oxidation?
- Loss of electrons
- Gain of oxygen
- Oxidation state increases
What is reduction?
- Gain of electrons
- Loss of oxygen
- Oxidation state decreases
What is a Reducing Agent?
- Electron donor
- A reducing agent is itself oxidised
What is an Oxidising Agent?
- Electron acceptor
- An oxidising agent is itself reduced
Acronym for Oxidation States?
U nder
M y
F ace
H ere’s
O ur
C hin
What is the oxidation state for U?
Uncombined elements = 0
What is the oxidation state for M?
Metals = Group number (1/2/3)
What is the oxidation state for F?
Fluorine = -1
What is the oxidation state for H?
Hydrogen = +1
What is the oxidation state for O?
Oxygen = -2
What is the oxidation state for C?
Chlorine (halogens) = -1
What does the roman numeral symbolise?
The oxidation state of the element
What are the rules for balancing half equations?
- Balance out the main atoms first
- Balance out O by using H2O
- Balance out H using H+
- Balance charge by using electrons
What are the rules for combining half equations?
- Make both equations contain the same number of electrons
- Add the reactants from both half equations together
- Add the products from both half equations together
- Cancel out the electrons and any other products/reactants if possible
Why is 1s2 2s2 2p5 a weaker reducing agent than 1s2 2s2 2p6 3s2 3p6 4s2?
The 2p electron is closer to the nucleus (smaller atom) than the 4s electron. This means the nuclear attraction is stronger so the 2p electron sis lost less easily than the 4s electron
What happens in a redox reaction?
Electrons are transferred from one element to another - one element is oxidised and the other is reduced
Define the term disproportionation
Where in the redox reaction, the oxidation states of atoms of the same element both increases and decreases
