Properties of Period 3 elements and their oxides

Question 1

What is the equation for sodiums reaction with water

Answer 1

2Na + 2H2O —> 2NaOH + H2

Question 2

What is the equation for magnesium’s reaction with water (cold)

Answer 2

Mg + 2H2O —> Mg(OH)2 + H2

Question 3

What is the equation for magnesium’s reaction with steam

Answer 3

Mg + H2O —> MgO + H2

Question 4

What is the equation for magnesium’s reaction with oxygen?

Answer 4

2Mg + O2 —> 2MgO

Question 5

What is the equation for aluminiums reaction with oxygen?

Answer 5

4Al + 3O2 —> 2Al2O3

Question 6

What is the equation for sodiums reaction with oxygen?

Answer 6

4Na + O2 —> 2Na2O

Question 7

What is the equation for silicons reaction with oxygen?

Answer 7

Si + O2 —> SiO2

Question 8

What is the equation for phosphorous’s reaction with oxygen?

Answer 8

4P + 5O2 —> P4O10

Question 9

What are the equations for sulphurs reaction with oxygen?

Answer 9

S + O2 —> SO2
2SO2 + O2 —> 2SO3

Question 10

How does melting point change of the oxides from Na2O —> SO3

Answer 10

The giant structures (the metal oxides and silicon dioxide) have high boiling points due to strong ionic and covalent bonds

The non metals all form VDW forces so have low Mp’s and Bp’s

Question 11

What is the equation for sodium oxides reaction with water? What is the pH of the product formed?

Answer 11

Na2O + H2O —> 2NaOH
14

Question 12

What is the equation for magnesium’s oxides reaction with water?

Answer 12

MgO + H2O —> Mg(OH)2

Question 13

What is the equation for aluminium oxides reaction with water?

Answer 13

Aluminium oxide is insoluble in water
7

Question 14

What is the equation for silicon oxides reaction with water?

Answer 14

Silicon dioxide is insoluble in water
7

Question 15

What is the equation for phosphorous oxides reaction with water?

Answer 15

P4O10 + 6H2O —> 4H3PO4
H3PO4 ⇌ H+ + H2PO4- (dissociates to this in the water)

Question 16

What is the equation for sulphur dioxides reaction with water?

Answer 16

SO2 + H2O —> H2SO3
H2SO3 ⇌ H+ + HSO3- (dissociates to this in the water)
2

Question 17

What is the equation for sulphur trioxides reaction with water?

Answer 17

SO3 + H2O —> H2SO4
H2SO4 ⇌ H+ + HSO4- (dissociates to this in the water)

Question 18

How does sodium oxide react with HCl

Answer 18

Na2O + 2HCl —> 2NaCl + H2O

Question 19

How does magnesium oxide react with HCl

Answer 19

MgO + 2HCl —> MgCl2 + H2O

Question 20

Why is aluminium oxide special

Answer 20

Its amphoteric

Question 21

How does aluminium oxide react with HCl

Answer 21

Al2O3 + 6HCl —> 2AlCl3 + 3H20

Question 22

How does aluminium oxide react with NaOH and H2O

Answer 22

Al2O3 + 2NaOH + 3H2O —> 2NaAl(OH)4

Question 23

How does silicon dioxide react with NaOH

Answer 23

SiO2 + 2NaOH —> Na2SiO3 + H2O

Question 24

How does phosphoric acid react with NaOH

Answer 24

H3PO4 + NaOH —> NaH2PO4 + H2O
NaH2PO4 + NaOH —> Na2HPO4 + H2O
Na2HPO4 + NaoH —> Na3PO4 + H2O

Question 25

How does SO2 react with NaOH

Answer 25

SO2 + NaOH —> NaHSO3
NaHSO3 + NaOH —> Na2SO3 + H2O

Question 26

How does sulphur trioxide react with NaOH

Answer 26

SO3 + 2NaOH —> Na2SO4 +H2O

Question 27

How does aluminium oxide react with H2SO4

Answer 27

Al2O3 + 3H2SO4 —> Al2(SO4)3 + 3H2O
SO4 = 2-
Al = 3+ but x2
Therefore 3 sulphates needed

Question 28

How to tell the difference between aqueous SO2 and aqueous SO3

Answer 28

Universal indicator
SO2 orange red
SO3 red

CaCO3
SO2 slower effervesce
SO3 faster effervesce

Question 29

How does aluminium oxide react with NaOH

Answer 29

Al2O3 + 2NaOH —-> 2NaAlO2 + H2O

Question 30

Formula and charge of phosphate ion

Answer 30

PO4 3-

Question 31

Formula and charge of an aluminate ion

Answer 31

Al(OH)4 1-

Question 32

Formula and charge of silicate ion

Answer 32

SiO3 2-