A2- Period 3 (inc. oxides)

Question 1

Write an equation for the reaction of sodium with water

Answer 1

Na(s) + H2O(aq) –> NaOH(aq) + ½H2 (g)

Question 2

Describe what is observed when sodium reacts with water

Answer 2

fizzing due to H2 being produced, moves on surface

Question 3

Write an equation for the reaction of magnesium with steam

Answer 3

Mg(s) + H2O(g) –> MgO(s) + H2(g)

Question 4

Describe what is observed when magnesium reacts with steam

Answer 4

Mg burns with bright white light, white solid formed

Question 5

Write an equation for the reaction of Na with oxygen

Answer 5

2Na + 1/2O2 –> Na2O

Question 6

Describe what is observed when reacts Na with oxygen

Answer 6

Na burns with orange/yellow flame, white solid produced

Question 7

Write an equation for the reaction of Mg with oxygen

Answer 7

Mg(s) + 1/2O2(g) –> MgO(s)

Question 8

Describe what is observed when Mg reacts with oxygen

Answer 8

Mg burns with bright white flame, white solid produced

Question 9

Write an equation for the reaction of Al with oxygen

Answer 9

4Al + 3O2 –> 2Al2O3

Question 10

Write an equation for the reaction of Al2O3 + NaOH

Answer 10

Al2O3 + 2NaOH + 3H2O –> 2 NaAl(OH)4

Question 11

Write an equation for the reaction of Si with oxygen

Answer 11

Si(s) + O 2 (g) –> SiO 2 (g)

Question 12

Describe what is observed when Si reacts with oxygen

Answer 12

Si burns with a white flame, grey solid formed

Question 13

Write an equation for the reaction of P with oxygen

Answer 13

P4 (s) + 5O2(g) –> P4O10(s)

Question 14

Describe what is observed when P reacts with oxygen

Answer 14

P burns with a white flame, white solid formed

Question 15

Write an equation for the reaction of S with oxygen

Answer 15

S8(s) + 8O2 (g) –> 8SO 2 (g)

Question 16

Describe what is observed when S reacts with oxygen

Answer 16

S burns with a blue flame, gaseous SO2 formed (turns UI red)

Question 17

Explain how to produce SO3

Answer 17

React SO2 with O2 with V2O5 catalyst

Question 18

Write an equation for the reaction of Na2O with water, state the
pH of the solution formed

Answer 18

Na2O + H2O –> 2NaOH
pH 14

Question 19

Write an equation for the reaction of MgO with water, state the
pH of the solution formed

Answer 19

MgO + H2O –> Mg(OH)2
pH 10

Question 20

Explain why MgO produces a less basic solution than Na2O

Answer 20

Mg(OH)2 is sparingly soluble in water, much lower OH - ion concentration

Question 21

Explain why Al2O3 and SiO2 do not react with water

Answer 21

lattice too strong to break

Question 22

Write an equation for the reaction of P4O10 with water, state the
pH of the solution formed

Answer 22

P4O10 + 6H2O –> 4H3PO4
pH 1-2

Question 23

Write an equation for the reaction of SO2 with water, state the
pH of the solution formed

Answer 23

SO2 + H2O –> H2SO3
pH 1-2

Question 24

Write an equation for the reaction of SO3 with water, state the
pH of the solution formed

Answer 24

SO3 + H2O –> H2SO4
pH 1-2

Question 25

What does amphoteric mean?

Answer 25

Can act as both an acid and a base

Question 26

Write an equation for the reaction of Al2O3 with HCl

Answer 26

Al2O3 + 6HCl –> 2AlCl3 + 3H2O

Question 27

Why is Na2O and water forms a solution with a higher pH than a solution formed from Mg(OH)2 and water?

Answer 27

• forms OH- ions
• Na2O is more soluble than Mg(OH)2