3.1.7 Ox. ,Red. , and Redox equations (physical chemistry)

Question 1

Define oxidation and reduction and relate this back to oxidation states

Answer 1

OILRIG
-Oxidation is the loss of electrons
-Oxidation state increases

-Reduction is gain of electrons
-Oxidation state decreases

Question 2

Define Oxidising Agent

Answer 2

Electron acceptor
It itself is reduced

Question 3

Define Reducing Agent

Answer 3

Electron donor
It itself is oxidised

Question 4

Rules for Oxidation states
-uncombined elements
-sum of ox. states in compounds
-simple ions
-complex ions

Answer 4

1. uncombined elements = 0
2. sum of all ox. states in a compound = 0
3. ox. states of a simple ion = its charge
4. sum of all ox. states in a complex ion = its charge

Question 5

Order in which to assign ox. states

Answer 5

Under - Uncombined Elements
My - Metals (1,2, and Al=+3)
Face - Fluorine = -1
Heres - Hydrogen = +1
Our - Oxygen = -2
Chin - Chlorine = -1

Question 6

Rules for balancing half equations

Answer 6

1. Balance atoms being ox. / red.
2. Balance O using H20
3. Balance H using H+
4. Balance charge using e-
   Always add to the more +ve side

Question 7

Rules for combining half equations

Answer 7

1. Multiply the whole equation so they both have the same number of electrons
2. Cancel out electrons
3. Write the equation with all reactants on the left side and all products on the right side

Question 8

Disproportionation

Answer 8

When the same species has been both oxidised and reduced in an equation

Question 9

Mg(s) + Cl2(g) –> MgCl2(s)
Identify the oxidation and reduction half equation and the oxidising and reducing agents

Answer 9

Oxidation:
Mg –> [Mg]2+ + 2e-
reduction:
Cl2 + 2e- –> 2Cl-

reducing agent : Mg
oxidising agent : Cl2