Period 3

Question 1

Sodium reaction with water
Observations:
Equation:
pH if product:

Answer 1

Sodium fizzes across surface and melts into a ball
Na + H2O —> NaOH + 0.5H2
pH NaOH : 12-14

Question 2

Magnesium reaction with water
Observations:
Equation:
PH product:

Answer 2

Very slow reaction and a few bubbles of H2
Mg + 2H2O —> Mg(OH)2 + H2
pH Mg(OH)2: 8-10

Question 3

Magnesium reaction with steam
Observations:
Equation:
PH product:

Answer 3

Bright white light and white powder forms (like burning)
Mg + H2O —> MgO + H2
MgO is insoluble so pH can’t be determined

Question 4

Aluminium reaction with water
Observations:
Equation:
PH product:

Answer 4

No reaction as coated with Al2O3

If coating is removed it reacts vigorously

Question 5

What period 3 elements don’t react with water ?

Answer 5

Silicon, Phosphorus, Sulfur

Question 6

Chlorine reaction with water
Observations:
Equation:
PH product:

Answer 6

Green solution (Cl(aq))
Blue litmus paper turns red then white due to acid then bleach 
Cl2 + H2O  HCl + HClO
pH HCl: around 2
HClO reacts with UV to form HCl

Question 7

What is disproportionation

Answer 7

This is where an element is both oxidised and reduced in the same reaction

Question 8

Sodium reacting with Oxygen
Observations:
Equation:
Basic or acidic ?

Answer 8

Yellow flame and white solid formed
2Na + 0.5O2 —> Na2O
Basic compound

Question 9

Magnesium reacting with Oxygen
Observations:
Equation:
Basic or acidic ?

Answer 9

Bright white light + white solid formed
2Mg + O2 —> 2MgO
Basic compound

Question 10

Aluminium reacting with Oxygen
Observations:
Equation:
Basic or acidic ?

Answer 10

Very slow reaction unless powder used
4Al + 3O2 —> 2Al2O3
Basic COMPOUND

Question 11

Formation of silicon dioxide

Observations:

Answer 11

Si + O2 —> SiO2

Very slow

Question 12

Formation of phosphorus pentoxide

Observations:

Answer 12

P4 + 5O2 — P4O10
White flame
White fumes

Question 13

Formation of sulfur(IV) dioxide

Observations:

Answer 13

S + O2 —> SO2
Blue flame
Fumes of gas with choking Oder

Question 14

P3 nonmetal oxides and metal oxides

Which are acdid and which is basic

Answer 14

Acidic - nonmetal

Basic - metal

Question 15

Structure of SiO2 ?

Answer 15

GIANT covalent

Question 16

Metal oxide + water form ?

Answer 16

Metal hydroxide

Question 17

pH of NaOH

Answer 17

12-14

Question 18

pH of Mg(OH)2

Answer 18

9-10 (is sparingly soluble)

Question 19

pH Al2O3

Answer 19

Insolube in water so doesn’t react

(Can react with acids and bases to form salts)-amphoteric

Question 20

Non metal P3 oxides + water forms ?

Answer 20

Forms acid counterpart
Eg
P4O10 + H2O —> H3PO4

Question 21

pH phosphoric acid

Answer 21

0-2(Strong acid)

Question 22

pH Sulfuric(IV)acid (H2SO3)

Answer 22

2-3(weak acid)

Question 23

pH Sulphuric (VI) acid (H2SO4)

Answer 23

0-1 (Strong acid)

Question 24

What two types of oxides react ?

Answer 24

Covalent and Ionic

Question 25

Why is Al2O3 special ?

Answer 25

Aluminium oxide is amphoteric which means it reacts with both acids and bases

Question 26

Can act as an acid or base

Answer 26

Amphoteric

Question 27

Why does Aluminium salts form acidic solutions

Answer 27

Al 3+ ion surrounded by 6 coordinate bonds from water (from O)
Al3+ polarises the water and has enough polarising power to break OH bonds forming H+

Question 28

Al2O3
acting as a base
Acting as a acid

Answer 28

Al2O3 + 6HCl —> 2AlCl3 + 3H2O

Al2O3 + 2NaOH + 3H2O —> 2NaAl(OH)4

Question 29

Reactions of [Al(H2O)6]3+ + OH-

Answer 29

[Al(H2O)6]3+ + OH- —>
[Al(H2O)5(OH)]2+ + H2O
(Neutral when neutral and becomes insoluble)