Periodicity of period 3 Oxides

Question 1

Sodium and water equation

Answer 1

Na(s) + H20(aq) —> NaOH(aq) + 1/2H2(g)

Question 2

Observations when sodium reacts with water

Answer 2

Na floats, fizzes due to H2 production, moves around surface of water

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 (MgO)

Question 5

Write an equation for the reaction of Na with oxygen

Answer 5

2Na(s) + 1⁄2O2(g) —> Na2O(s)

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(s) + 3O2(g) —> 2Al2O3(s)

Question 10

Describe what is observed when Al reacts with oxygen

Answer 10

Al burns with white flame, white solid produced

Question 11

Write an equation for the reaction of Si with oxygen

Answer 11

Si(s) + O2(g) —> SiO2(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) —> 8SO2(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

State the type of bonding in the oxides of period 3

Answer 18

Na2O, MgO, Al2O3 - ionic
SiO2 – macromolecular (giant covalent)
P4O10, SO2, SO3 = Van der Waals/simple molecular

Question 19

Write equation for reaction of Na2O with water + pH

Answer 19

Na2O + 2H2O —> 2NaOH
pH 14

Question 20

Write equation for reaction of MgO with water
State pH

Answer 20

MgO + H2O —> Mg(OH)2
pH 10

Question 21

Why does MgO form less basic solution than Na2O

Answer 21

Mg(OH)2 is sparingly soluble in water, lower OH- conc

Question 22

Why doesn’t Al2O3 react in water

Answer 22

Lattice too strong to break

Question 23

Why doesn’t SiO2 react in water

Answer 23

Lattice too strong to break

Question 24

Equation for P4O10 reaction with water + pH

Answer 24

P4O10 + 6H2O —> 12H+ + 4PO4^3-
pH 1-2

Question 25

Equation for reaction of SO2 with water
+pH

Answer 25

SO2 + H2O —> 2H+ + SO3^2-
pH 1-2

Question 26

Equation of reaction of SO3 with water
+pH

Answer 26

SO3 + H2O —> 2H+ + SO4^2-
pH 1-2

Question 27

why do basic oxides form alkaline solutions

Answer 27

Have free O^2- ions that react with water to produce OH- ions
O^2- + H2O —> 2OH-

Question 28

What does amphoteric mean

Answer 28

Can act as both acid and base

Question 29

What period 3 oxide is amphoteric

Answer 29

Al2O3

Question 30

Write equation for reaction of Al2O3 with HCl

Answer 30

Al2O3 + 6HCl —> 2AlCl3 + 3H2O

Question 31

Write equations for reaction of Al2O3 with NaOH

Answer 31

Al2O3 + 2NaOH + 3H2O —> 2NaAl(OH)4