Periodicity

Question 1

what pH does the solution make when Na2O reacts with water

Answer 1

pH 14
NaOH solution

Question 2

what pH does the solution make when MgO reacts with water

Answer 2

pH 10
Mg(OH)2 solution

Question 3

reaction when Al2O3 is put in water

Answer 3

no reaction- it is insoluble

Question 4

reaction of Al2O3 and acid

Answer 4

Al2O3 + 6H+ ——> 2Al^3+ + 3H2O

Question 5

reaction of Al2O3 and alkali

Answer 5

Al2O3 + OH- + 3H2O —–> 2Al(OH)4^-

Question 6

nature of metal oxides

Answer 6

basic

Question 7

nature of aluminium oxide

Answer 7

amphoteric

Question 8

reaction of SiO2 and water

Answer 8

no reaction (insoluble)

Question 9

reaction of SiO2 and alkali

Answer 9

SiO2 +2OH- —–> SiO3^2- +H2O
must use hot, conc. alkali

Question 10

nature of non-metal oxides

Answer 10

acidic

Question 11

Reaction of P4O10 and water

Answer 11

reaxts violently
P4O10 +H2O —-> H3PO4
pH 0

Question 12

reaction of SO2 and water

Answer 12

dissolves
SO2 +H2o —-> H2SO3
pH 3

Question 13

reaction of SO3 and water

Answer 13

reacts violently
SO3 + H2O —-> H2SO4
pH 0

Question 14

Steps to extract titanium

Answer 14

Ti02 (solid) is converted to TiCl4 at 900 degrees C
TiCl4 is purified by fractional distillation
Ti is extracted by Mg at 500 degrees C

Question 15

equation for removing SO2 from atmosphere

Answer 15

SO2 + CaO —-> CaSO3

Question 16

How to identify halide ions

Answer 16

Add acidified silver nitrate (acidify with nitric acid)
white/cream/yellow precipitate will form

Question 17

How to identify silver halide compounds if colours are similar

Answer 17

Add ammonia

Question 18

Reactions of silver halides with ammonia

Answer 18

AgCl- dissolves in dilute
AgBr- dissolves in conc.
AgI- insoluble

Question 19

Reactions of fluoride and chloride ions in H2SO4
what kind of reaction is this

Answer 19

NaF + H2SO4 —–> HF + NaHSO4
acid-base reaction

Question 20

Second (redox) reaction of bromide ions and H2SO4

Answer 20

2Br- + 2H+ + H2SO4 —–> Br2 + SO2 + 2H2O

Question 21

Overall reduction and oxidation reactions of bromide ions and H2SO4

Answer 21

2Br- —-> Br2 + 2e-

H2SO4 + 2H+ —–> SO2 + 2H2O

Question 22

Last two redox equations of iodide ions and H2SO4

Answer 22

H2SO4 + 6I- + 6H+ —–> S + 3I2 + 4H2O

H2SO4 + 8I- + 8H+ —–> H2S + 4I2 + 4H2O

Question 23

disproportionation reactions of chlorine in water (no sun)

Answer 23

Cl2 + H2O <—–> HClO + HCl

Question 24

reaction of chlorine in sunlight

Answer 24

2Cl2 + 2H2O —-> 4HCl +O2

Question 25

Reaction of Chlorine to form bleach and conditions

Answer 25

cold, dilute NaOH Cl2 + 2NaOH -----> NaClO + NaCl + H2O

Question 26

what structure is SiO2

Answer 26

macromolecular

Question 27

what structures are P4O10 and SO2

Answer 27

simple molecular

Question 28

structures of sodium oxide, magnesium oxide and aluminium oxide

Answer 28

giant ionic lattice

Question 29

why is the melting point of aluminium oxide lower than expected

Answer 29

has some covalent character as the highly polarising Al3+ ion distorts the electron cloud

Question 30

why does magnesium oxide make a less alkali solution in water than sodium oxide

Answer 30

it is less soluble so only partially dissociates

Question 31

why are aluminium oxide and silicone oxide insoluble

Answer 31

aluminium oxide- bonding too strong so ions can't be separated silicone oxide- macromolecular structure