Chapter 7~ Redox Reactions

Question 1

Definition of Oxidation :

Answer 1

°the addition of oxygen, removal /loss of electrons or the increase in oxidation state of a substance.

Also : the loss of Hydrogen

Question 2

Definition of Oxidation state/number :

Answer 2

A number given to an atom ⚛ in a compound that describes to what degree that it is either oxidised or reduced

Question 3

Definition of oxidising agent

Answer 3

°a reactant that increases the oxidation state of (or removes electrons from) another reactant. It itself is reduced.

Question 4

Definition of a redox reaction :

Answer 4

°it is a chemical reaction in which oxidation and reduction happen simultaneously

Question 5

Definition of reducing agent:

Answer 5

°a reactant that decreases the oxidation state (or adds electrons to) another reactant. It itself is oxidised.

Question 6

Definition of reduction is :

Answer 6

° the removal of oxygen, addition/gain of electrons or decrease in oxidation state of a substance.

Question 7

Definition of half-equation :

Answer 7

In a redox reaction, it is an equation that displays either oxidation or a reduction

Question 8

There are 2 main ways of determining whether a substance has be oxidised or reduced during a chemical reaction :

Answer 8

1. Electron transfer

2. Changes in oxidation state

Question 9

OIL stands for 🛢 :

Answer 9

Oxidation is loss of electrons

Question 10

RIG stands for :

Answer 10

Reduction Is Gain in electrons

Question 11

The 6 oxidation state rules :

Answer 11

1. The oxidation state of any uncombined element is zero. E. G S8=0
2. In compounds many atoms/ions have fixed oxidation states :
   ¬group one =+1
   ¬group two=+2
   ¬Flourine is always =-1
   ¬hydrogen =+1 (except in metal hydrides where it is - 1 e.g. In NaH)
   ¬Oxygen =-2( except in peroxides, where it is - 1 and in Fe20=+2)
3. Oxidation state of an element in a monatomic ion is always the same as its charge
4. Sum of Oxidation states in a compound is zero
5. The sum of the oxidation state in an ion =to the charge on the ion
6. In either a compound / an ion, the more electronegative element is given the negative oxidation state

Question 12

The 4 steps in balancing chemical equations using oxidation states :

Answer 12

1. write the unbalanced equation and identify the atoms which change oxidation state
2. deduce the oxidation state changes
3. balance the oxidation state charges
4. Balance the atoms ⚛