REDOX Flashcards
Redox Reactions
caused by competition of atoms for electrons
Oxidation
the LOSS of electrons, charge becomes more positive
Reduction
the GAIN of electrons, charge becomes more negative
Oxidation number
the “apparent change” on an atom in a compound, due to difference in electronegativity and bonding
Ion
charge an atom becomes when it gains or loses electrons
Redox Rule #1
- neutral compounds must sum to the total charge of zero (NaCl, AlPO4)
Redox Rule #2
- polyatomic ions have a sum total = to the ion’s charge (PO4 ^ -3 = total charge = -3)
Redox Rule #3
any atom uncombined has a oxidation of zero, because atoms are neutral
Redox Rule #4
a monoatomic ion has a oxidation that equals its ion charge
Electronegativity
the attraction for another atom’s electrons
Redox Rule #5
in binary compounds the more electronegative element is assigned FIRST (more active non-metal)
Redox Rule #6
all elements in group 1 and 2 have the oxidation states +1 and +2 and aluminums oxidation state is +3
Redox Rule #7
fluorine will always have a -1 oxidation number
Redox Rule #8
because fluorine is always -1, oxygen can be +
2, in peroixde oxygen is -1
Redox Rule #9
hydrogen almost always will be +1 but if it combines with a metal to make a hydride it will be -1
Redox
an overall reaction that is defined by the transfer of electrons and can be broken down into 2 reactions that both occur simultaneously
Oxidizing Agent
the substance that makes something else undergo oxidation
Reducing Agent
any substance that makes something else gain electrons
Half Reaction
an equation which shows only a reduction or oxidation (shows conservation of mass, charge, and energy)
Voltaic Cells
are electrochemical cells which involve a spontaneous redox reaction where chemical energy is converted into electrical energy
Anode
in a voltaic cell the anode is - and is the site of oxidation
Cathode
in a voltaic cell the cathode is + and is the site of reduction
flow of electrons in a voltaic cell
electrons move from anode to cathode through the wire
Anode and Cathode - mass size
- anode decreases in mass/size
- cathode increases in mass/size
What is happening with the salt bridge?
ions both negative and positive are moving through the salt bridge in the direction of the electrode with same charge to maintain neutrality, then the battery will die and voltage will read zero to come to a state of equilibrium
Maximum Battery Voltage or Cell Potential formula
cell potential (V) = reduction potential (v) - oxidation potential (v)
Electrolytic cells
electrolysis is a non-spontaneous reaction that requires electricity; process by which we use elec t break down a compound into its component molecule
Allotrope
one or more form of a chemical element that can exist in the same physical state
Mass Number
total number of protons and neutrons in an atom
Heat of Vaporization
the amount of heat needed to turn 1 g of a liquid into a vapor