Redox

Question 1

What doe the oxidation state relate to ?

Answer 1

realtes to the the group number / ion number times by coefficient

Question 2

What do all the compounds have to equal to ?

Answer 2

Zero

Question 3

In pure elements (Cr , Cl , Br ) what’s the oxidation state ?

Answer 3

They dont have one (zero)

Question 4

What does a oxidation state show ?

Answer 4

how many electrons an atom has gained or lost

Question 5

Can electronegativities be used to work out oxidation states

Answer 5

Yes

Question 6

What is the oxidation state of oxygen and when is it not ?

Answer 6

-2, except in peroxides an F20 , where fluorine is more electronegative so oxygen would be +2

Question 7

What is the oxidation state of hydrogen and what are the exceptions

Answer 7

+1 , except in metal hydrides where hydrogen is -1

Question 8

What is the oxidation state of chlorine and what are exceptions?

Answer 8

usually -1 , except in a compound with fluorine or oxygen

Question 9

What are the oxidation states of group 1 metals ?

Answer 9

always +1

Question 10

What are the oxidation states of group 2 metals

Answer 10

always + 2

Question 11

how soluble are common salts of sodium , potassium and ammonium ?

Answer 11

All soluble

Question 12

How soluble are nitrates ?

Answer 12

All soluble

Question 13

How soluble are sulfates ?

Answer 13

soluble except lead , barium and calcium

Question 14

How soluble are chlorides ?

Answer 14

soluble except sliver and lead

Question 15

How soluble are carbonates ?

Answer 15

Insoluble except sodium , potassium and ammonium

Question 16

how soluble are hydroxides ?

Answer 16

Insoluble except sodium , potassium , ammonium and barium

Question 17

How soluble are oxides ?

Answer 17

Insoluble except sodium and potassium

Question 18

Rules for writing half - equations

Answer 18

1. Balance the element which is changing oxidation state
2. Balance the O’s by adding H2O
3. Balance the H’s by adding H+
4. Balance charge by adding electrons