Unit 4 - Oxidation/Reduction

Question 1

What is oxidation and reduction?

Answer 1

Oxidation is the process of a substance gaining oxygen OR loosing electrons

Reduction is the contrary, gaining electrons OR loosing oxygen

Question 2

Oxidation and reduction equation

Answer 2

Oxidation:

X —> x+ + e-

Eg- 2Mg + O2 —> 2MgO

Reduction:

X + e- —> x-

Eg- 2MgO —> 2Mg + O2

Question 3

Metals and reactivity

Answer 3

Elements with for example 7 when they gain and electron from an element from group 1 they become 1-.

Potassium is more reactive than Lithium because potassium is lower in the periodic table, also it contains one more shell so it is easier to loss the electron but there is electro shielding so more energy is required for to obtain that electron.

An ore is a natural solid material from which a metal or valuable mineral can be extracted profitably.

Question 4

Neutralisation of reactions
Respond to the following:

Acid + metal —>
Acid + metal oxide —>
Acid + metal hydroxide —>
Acid + metal carbonate —>

Answer 4

Acid + metal —> Salt + Hydrogen
Acid + metal oxide —> Salt + water
Acid + metal hydroxide —> Salt + water
Acid + metal carbonate —> Salt + CO2 + H2O

Question 5

Salts:

Hint there is 4 of them

(GOOD NOTES page 62)

Answer 5

Sulphate ion: SO4 2-
Nitrate ion: NO3 1-
Phosphate ion: P2O3 3-
Hydrochloride ion: OH -

Eg: Al + SO4 —> Al2 (SO4)3 + H2