Redox Flashcards
OILRIG
oxidation is loss of electrons
reduction is gain of electrons
what is a redox reaction
reaction that involves reduction and oxidation in the same reaction
Reducing agents…
are the ones that LOSE electrons themselves
Oxidising agents…
are the ones that themselves GAIN the electrons
uncombined elements oxidation states are
ZERO eg cl2 Fe O2
ions oxidation states
Aluminium oxidation state
eg Cl- = -1 Ca2+= 2+
Al= ALWAYS 3+
oxidation state of hydrogen and hydrides
1) in hydrogens ALWAYS +1
2) in Hydrides ALWAYS -1
oxidation states for cholrine
usually -1
BUT if a “F” or “O” is present then the oxidation state will be positive
eq ClF3= +3
oxidation state of Fluorine
Always -1
oxidation state of oxygen and peroxides
oxygen= 2- peroxide= 2+
EG in H2O2= 2+
when stating oxidation elements
always state it for the single element
EG for O2 work out oxidation state of the “O” ONLY not the “O2”
iron (II)/ (III) oxide has an oxidation state of ??
2+ 3+ respectively
what do half equations show
and what must they all have
1) show reduction and oxidation in 2 equations
2) all half equations must have electrons in them
Rules for Balancing half equations
1) write down the species before and after the reaction
2) Balance any atoms EXCEPT “H” or “O”( do that later)
3) Balance any oxygens IF PRESENT with water
4 ) Balance hydrogens IF PRESENT with H+ ions
5) Balance charges with electrons electrons ( e-)
COMBINING half equations to create FULL IONIC equations
- THERE SHOULD BE NO ELECTRONS IN THE FINAL EQUATION
- work them out like simultaneous equations
