Chapter 14 and 15 Flashcards
Losing Electrons
Oxidation
Gaining Electrons
Reduction
Oxidising Agent
Causes Oxidisation
Reducing Agent
Causes Reduction
Reductant
Undergoes Oxidation, loses electrons
Oxidant
Undergoes Reduction, Gains Electrons
Rules for Assigning Oxidation Numbers
- Oxidation numbers for atoms are zero
- Oxygen is -2
- Hydrogen in its compound is +1
- H- has the oxidation number is -1
Oxidation numbers to identify REDOX
- If the right side, the product, has a higher oxidation number than the left side, the reactant, the reactant molecule or atom is said to have been oxidized.
- Reduction is gain, Oxi is Loss
- No change = not redox
What Will react with H+ to form Hydrogen, H2
Metals below Copper, metals above will not react to form hydrogen
What metals will react with Water
All metals below Zn
Halogens
F2 will displace Cl-, Br-, I-
Cl will displace Br-, I- and NOT F-
Br will displace I-,
I2 will not displace ANYTHING
Water + Metal Equation
2H2O (l) + 2 e’ -> H2(g) + 2OH- (aq)
- This is the reduction reaction
Metal + Acid
2H+(aq) + 2e’ -> H2(g)
Strong Reducting Agents
Everything below Mn(s), ON THE RIGHT
Strong Oxidising Agents
Everything Above O2(g) + 4H+, ON THE LEFT
Forward Reaction
Reduction
Reverse Reaction
Oxidation
Halogens
cause oxidation oif another species
- UNDERGOES REDUCTION
-
Disproportination
- when a single substance undergoes both reduction and oxidation
- H202-> h20 + 02
- Cu+ -> Cu + Cu2+
electrolytic cells
- uses an electric current to bring about a chemical reaction
- RED CAT
- reduction at the cathode
- negative ions go to anode
- positive ions go to cathode
Cathode
negative
anode
positive
flow of electron
anode -> cathode, flow up then down to cathode
Electrolysis of solutions
- water can behave as an oxidant or reductant
- becomes oxidised,
- 2h2O -> O2 + 4H+ + 4e’
electrolysis definition
- passage of an electric current through an electrolyte with oxidation taking place at the anode and reduction at the cathode
What is produced at the cathode and anode
- molten metal halides produce the metal at the cathode
and halogens at the anode
