Chem5 - Group 3 forming oxides and oxides + H20

Question 0

Magnesium with water describe and write reaction (5)

Answer 0

~very slow reaction with water but burns in steam
~Mg(s) + H2O (g) –> MgO (s) + H2 (g)
~MgO (s) is the white powder formed
~with cold water if react would form magnesium hydroxide Mg (s) + 2H2O (l) –> Mg(OH)2 (aq) + H2 (g)
~can use poshly explained ‘squeeky pop’ test on both

Question 1

Describe and write the equation for the reaction sodium with water (4)

Answer 1

~2Na (s) + 2H2O (l) –> 2NaOH (aq) + H2 (g)
~Na reacts rapidly and moves across surface of H2O
~burns with a white flame
~describe poshly the ‘squeeky pop’ test

Question 2

Describe and write equation for reaction of aluminium with water (2)

Answer 2

~no reaction

~as protective layer of Al2O3 on surface

Question 3

Reaction sodium and oxygen describe and write equation for the reaction (3)

Answer 3

~4Nan(s) + O2 (g) –> 2Na2O (s)
~burns with a yellow flame
~produces white solid mixture of sodium oxide

Question 4

Describe and write the equation for the reaction of magnesium and oxygen (3)

Answer 4

~Mg burns in Oxygen with an intense white flame
~forms white compound MgO
~2Mg(s) + O2 (g) –> 2MgO(s)

Question 5

Describe and write the equation for the reaction of Aluminium in Oxygen (4)

Answer 5

~Al will burn in O2 with a white flame
~if it is powdered
~otherwise strong oxide layer on Al tends to inhibit reaction
~2Al(s) + 3/2O2 (g) –> Al2O3 (s)

Question 6

Describe and write equation for reaction of Silicon with Oxygen (2)

Answer 6

~Si burns in O2 if heated strongly enough

~Si(s) + O2(g) –> SiO2 (s)

Question 7

Describe and write equation for the reaction of Phosphorus with Oxygen (5)

Answer 7

~spontaneously combusts in air/oxygen
~producing a white flame 
~and clouds of white smoke, phosphorus (V) oxide
~hence stored underwater
~P4 (s) + 5O2 (g) --> P4O10 (s)

Question 8

Describe and write equation for the reaction of Sulphur with Oxygen (5)

Answer 8

~Sulphur burns in air or oxygen on gentle heating
~with a pale blue flame
~produces pale yellow sulphur dioxide gas
~SO2 reacts with O2 in atmosphere to form SO3 which can then react with water vapour to produce H2SO4 i.e. Acid rain
~S (s) + O2 (g) –> SO2 (g) (pale yellow gas)

Question 9

Describe and write equation for the reaction of Chlorine with Oxygen (1)

Answer 9

~despite having several oxides, chlorine won’t react directly with oxygen

Question 10

Describe and write equation for the reaction of Argon and Oxygen (1)

Answer 10

~doesn’t react

Question 11

Write the equation for the reaction of sodium oxide and water and give the nature of the product formed (2)

Answer 11

~Na2O (s) + H2O (l) –> 2NaOH (aq)
~strong base
~pH 13

Question 12

Write the equation for the reaction of magnesium oxide and water and give the nature and describe the product formed (5)

Answer 12

~MgO (s) + H2O (l) --> Mg(OH)2 (aq)
~weak base
~pH 10
~white suspension
~sparingly soluble

Question 13

What happens when aluminium oxide is added to water and give the nature of the product formed (2)

Answer 13

~Al2O3 is insoluble

~due to high lattice enthalpy

Question 14

Write the equation for the reaction of silicon dioxide and water and give the nature of the product formed (2)

Answer 14

~Doesn’t react with water

~has strong covalent bonds (its sand!)

Question 15

Write the equation and describe the reaction of phosphorus (V) oxide and water and give the nature of the product formed (4)

Answer 15

~P4O10 + 6H2O –> 4H3PO4
~phosphoric acid produced, very strong acid
~pH 0
~reacts violently with H2O!!

Question 16

Write the equation for the reaction of sulphur dioxide and water and give the nature of the product formed (3)

Answer 16

~SO2 (g) + H2O (l) –> H2SO3 (aq)
~sulphurous acid, weak acid
~pH 3

Question 17

Write the equation for the reaction of sulphur trioxide and water and give the nature of the product formed (3)

Answer 17

~SO3 (g) + H2O (l) –> H2SO4 (aq)
~sulphuric acid, strong acid
~pH 1