Chapter 16- Redox

Question 0

Reduction

Answer 0

Gain of electrons

Question 1

Oxidation

Answer 1

Loss of electrons

Question 2

Redox half equations

Answer 2

Na->Na(pos)+e(neg)

For overall redo. Equation balance charges

Question 3

Oxid/reductant

Answer 3

Cause the other atom to do so

Question 4

Oxidation rules

Answer 4

An increase in oxidation number means oxidation has occurred

1. Ox # of a free element is 0
2. Ox # of a simple ion is equal to that ion
3. In compounds
   a. Ox # of main group metals are equal to valency
   b. Ox # of fluorine is -1
   c. Ox # of hydrogen is 1 with non-metals and -1 with metal hydrides
   d. Ox # -2 unless in peroxides which ox # is 2
4. In neutral compounds ox # is 0
5. Polyatomic ions have ox # equal to charge

Question 5

Electrode at which oxidation takes place

Answer 5

Anode

Question 6

Electrode at which reduction takes place

Answer 6

Cathode

Question 7

Process of rust

Answer 7

2Fe(s)+O2(aq)+2H2O(l)->2Fe+++4HO[-] occurs at electrodes
Fe starts from anodic pit and ions move towards cathode where…
Fe+++2OH-->Fe(OH)2(s){green dust} which in the presence of oxygen and water reacts as follows 4Fe(OH)2(s)+O2(aq)+2H2O(l) ->4Fe(OH)3(s){brown dust)

Question 8

Impressed current catholic protection

Answer 8

Flow of low voltage causes iron to be - charged and thus act as a cathode (not an anode) so oxidation can not occur (would produce more electrons)

Question 9

Sacrificial protection

Answer 9

A more easily oxidised metal is used to act as an anode there by making iron the cathode preventing the formation of Fe[++] ions

Question 10

Balancing complex redox equations

Answer 10

Kohes 
Key element
Oxygen (H2O)
Hydrogen (H+)
Electrons 
States

Question 11

An oil rig cat

Answer 11

Anode oxidation

Reduction cathode

Question 12

For spontaneous redox…

Answer 12

Oxidant must be stronger