Period 3 and their oxides Flashcards
What is the general equation when a metal and water react
Metal + water –> metal hydroxide + Hydrogen
What are the 2 observations when sodium reacts with water
Na fizzes on the surface of the water
Na Burns with a yellow flame
What is the equation for the reaction of Na with water
2Na(s) + 2H2O(l) –> 2NaOH(aq) + H2(g)
What is the ionic equation for the reaction of Na with water
2Na(s) + 2H2O(l) –> 2Na+(aq) + 2OH-(aq) + H2(g)
What is observed when Mg reacts with water
Reacts very slowly forming a few bubbles
What is observed when Mg reacts with steam
Burns with a white flame to form white powder
What is the equation for when Mg reacts with water
Mg(s) + 2H2O(l) –> Mg(OH)2(s) + H2(g)
What is the equation for when Mg reacts with steam
Mg(s) + H2O(g) –> MgO(s) + H2(g)
What is the general formula for a period 3 element + oxygen
Period 3 element + oxygen –> Period 3 metal oxide
State what type of bonding metal oxides have and explain why this occurs
Large difference in electronegativity leads to ionic bonding
State what type of bonding non metal oxides have and explain why this occurs
Small difference in electronegativity leads to covalent bonding
Give 3 examples of metal oxides
Na2O
MgO
Al2O3
Give 4 examples of non metal oxides
SiO2
P4O10
SO2
SO3
What is the equation for when Na reacts with oxygen
4Na(s) + O2(g) –> 2Na2O(s)
What type of structure is Na2O
Ionic lattice
Describe the melting point of Na2O and explain why is has this melting point
Na2O has a high melting point
Large amount of energy is required to break the strong
electrostatic attraction between oppositely charged ions in the lattice
What is observed when Na reacts with oxygen
Na burns with yellow flame to give a white solid
What is the equation for the reaction of Mg with oxygen
2Mg(s) + O2(g) –> 2MgO(s)
What is the structure of MgO
Ionic lattice
Describe the melting point of MgO and explain why is has this melting point
High melting point
Large amount of energy is required to break the strong
electrostatic attraction between oppositely charged ions in the lattice
State and explain which has a higher melting pint, MgO or Na2O
MgO has a higher melting point than Na2O
Mg2+ ions are smaller and have a greater charge.
Therefore Mg2+ has a larger charge density which attracts the O2- ion more strongly
What is observed when Mg reacts with oxygen
Mg burns with a bright white flame giving off white fumes and a white solid
What is the equation for when Al reacts with oxygen
2Al(s) + 1.5O2(g) –> Al2O3(s)
What kind of bonding is in Al2O3
Ionic with covalent character
What type of structure is Al2O3
Ionic lattice
Describe the melting point of Al2O3 and explain why is has this melting point
High melting point
Large amount of energy is required to break the strong electrostatic
attraction between oppositely charged ions in the lattice
Explain why Al2O3 displays covalent character
Due to polarising nature of Al3+ ions, Al2O3 has covalent character in addition to its ionic attraction
What is observed when Al reacts with oxygen
Burns with white flame to give a white solid
Are metal oxides basic or acidic
Basic
What are the 3 metal oxides to remember
Na2O
MgO
Al2O3
Are non metal oxides basic or acidic
Acidic
What is the equation for the reaction when Si reacts with oxygen
Si(s) + O2(g) –> SiO2(s)
What is the structure of SiO2
Giant covalent
Describe the melting point of SiO2 and explain why is has this melting point
High melting point
Large amount of energy is required to break the many strong covalent bonds between atoms that hold the lattice together
What is observed when Si reacts with oxygen
Burns with white flame to give a white solid
What is the equation for the reaction when P4 reacts with oxygen
P4(s) + 5O2(g) –> P4O10(s)
What is the structure of P4O10
Simple molecular
Describe the melting point of P4O10 and explain why is has this melting point
Low melting point
Little energy is required to break weak Van der Waal’s forces of attraction between the molecules
Explain why P4O10 has a higher melting point compared to SO2 and SO3
P4O10 is larger, and has more electrons
Therefore has stronger Van der Waal’s forces between the
molecules and hence higher MP
What is observed when P4 reacts with oxygen
Burns with white flame to give a white solid
What is P4
White Phosphourous
Why is P4 extremely dangerous
White phosphorus spontaneously ignites in air
What are the two equations for when Sulfur reacts with oxygen
1/8S8(s) + O2(g) –> SO2(g)
1/8S8(s) + 1.5O2(g) –> SO3(l)
What is the structure of SO2
Simple molecular
Describe the melting point of SO2 and explain why is has this melting point
Low melting point
Little energy is required to break the weak Van der
Waal’s forces of attraction between the molecules
What is observed when S8 reacts with oxygen
Burns with a blue flame giving off a pungent gas
What is the structure of SO3
Simple molecular
Describe the melting point of SO3 and explain why is has this melting point
Low melting point
Little energy is required to break weak Van der Waal’s
forces of attraction between the molecules
State and explain which has a higher melting point, SO3 or SO2
SO3
SO3 is larger then SO and has more electrons therefore has stronger Van der Waal’s forces between the molecules and so a higher MP/BP
What are the 4 non metal oxides to remember
SiO2
P4O10
SO2
SO3
Why are metal oxides basic
They contain the oxide ion (O2-)
What is the general ionic equation when O2- ions react with water
O2-(aq) + H2O(l) –> 2OH-(aq)
What is the general ionic equation when O2- ions react with an acid
O2-(aq) + H+(aq) —> OH-(aq)
What is the equation for the reaction when Na2O reacts with water
Na2O(s) + H2O(l) —> 2NaOH(aq)
What is observed when Na2O reacts with water
White solid dissolves in a violent, highly exothermic reaction giving a colourless solution
What is the colour of the product in this reaction: Na2O(s) + H2O(l) —> 2NaOH(aq)
Colourless
State the pH of NaOH and explain the strength of this base
pH - 14
NaOH fully dissociates and so it is a strong base
What is the equation for the full dissociation of NaOH
NaOH(aq) ⇌ Na+(aq) + OH-(aq)
What is the ionic equation for the reaction of Na2O and water
O2-(aq) + H2O(l) –> 2OH-(aq)
Describe the solubility of Na2O
insoluble
Describe the solubility of MgO
MgO is sparingly soluble
What is the equation for the reaction when MgO reacts with water
MgO(s) + H2O(l) ⇌ Mg(OH)2(s)
What is observed when MgO reacts with water
White solid is produced (Mg(OH)2(s))
State the pH of Mg(OH)2 and explain the strength of this base
pH - 9
Mg(OH)2 is sparingly soluble and therefore partially dissociates and so is a weak base
What is the equation for the partial dissociation of Mg(OH)2
Mg(OH)2 (aq) ⇌ Mg2+(aq) + 2OH-(aq)
What happens when Al2O3 reacts with water
Nothing
Insoluble
Explain why Al2O3 is insoluble
Lattice enthalpy is much greater than the hydration enthalpy
Therefore enthalpy of solution is very positive
Thus water cannot supply enough energy to break the ionic lattice
Explain how Na2O is insoluble in water
When it reacts with water it is an irreversible reaction
What is the pH of Al2O3 when reacts with water
pH- 7
(Insoluble)
How does Al2O3 act as a protective layer to Al
Al2O3 is inert so an Al2O3 layer is impermeable to air and water and protects any Al underneath from further oxidation.
What is the pH of SiO2 when it reacts with water
pH - 7
(insoluble)
Describe the solubility of SiO2
Insoluble
Why is SiO2 insoluble in water
Bond enthalpy is much greater than the hydration enthalpy
Therefore enthalpy of solution is very positive
Thus water cannot supply enough energy to break the many strong covalent bonds between atoms in the lattice
What is SiO2
Sand
What is observed when SiO2 reacts with water
Nothing
(insoluble)
What is observed when P4O10 reacts with water
White solid dissolves in a violent, highly exothermic reaction to
give a colourless solution
What is the equation for when P4O10 reacts with water
P4O10(s) + 6H2O(l) –> 4H3PO4(aq)
State the pH of H3PO4 and explain the strength of this acid
pH - O
H3PO4 fully dissociates and so is a strong acid
What is the ionic equation for when P4O10 reacts with water
P4O10(s) + 6H2O(l) –> 12H+(aq) + 4PO43-(aq)
What is the equation for the full dissociation of H3PO4
H3PO4(aq) ⇌ 3H+(aq) + PO43-(aq)
Draw the structure of both phosphoric acid and phosphate ion
Central P with 3 OH and 1 double bond O for H3PO4
Central P with 3 O- and 1 double bond O for PO43-
What is observed when SO3 reacts with water
Colourless liquid dissolves and reacts vigorously to give a colourless solution
What is the equation for the reaction when SO3 reacts with water
SO3(l) + H2O(l) –> H2SO4(aq)
State the pH of H2SO4 and explain the strength of this acid
pH - 0
H2SO4 fully dissociates and so is a strong acid
What is the equation for the full dissociation of H2SO4
H2SO4(aq) ⇌ 2H+(aq) + SO42-(aq)
What is the ionic equation for the reaction when SO3 reacts with water
SO3(l) + H2O(l) –> 2H+(aq) + SO42-(aq)
Draw the structure of Sulfuric acid and sulfate ion
Central S with 2 OH and 2 double bond O bonded for H2SO4
Central S with 2 O- and 2 double bond O bonded for SO42-
What is observed when SO2 reacts with water
Colourless gas dissolves and reacts to give a colourless solution
What is the equation for the reaction when SO2 reacts with water
SO2(g) + H2O(l) –> H2SO3(aq)
What is the ionic equation for the reaction when SO2 reacts with water
SO2(g) + H2O(l) –> 2H+(aq) + SO32-(aq)
State the pH of H2SO3 and explain the strength of this acid
pH - 3
H2SO3 partially dissociates and so is a weak acid
What is the equation for the partial dissociation of H2SO3
H2SO3(aq) ⇌ 2H+(aq) + SO32-(aq)
Draw the structure for Sulfurous acid and Sulfite ion
Central S with 2 OH and 1 double bond O bonded for H2SO3
Central S with 2 O- and 1 double bond O bonded for SO32-
Explain the difference in the position of the equilibrium between these 2 equations:
1) H2SO4(aq) ⇌ 2H+(aq) + SO42-(aq)
2) H2SO3(aq) ⇌ 2H+(aq) + SO32-(aq)
SO32- is not as stable as SO42- so equilibrium 2 lies further to the LHS compared to H2SO4
What ion does Na2O produce when it reacts with an acid
Na+
Does Na2O react with an acid or base ?
Acid
(Doesn’t react with base)
Does MgO react with an acid or base ?
Acid
(Doesn’t react with base)
Does Al2O3 react with an acid or base ?
Both
What ion does MgO produce when it reacts with an acid
Mg2+
What ion does Al2O3 produce when it reacts with an acid
Al3+
What is an Amphoteric oxide mean
One which is capable of reacting with both acids and bases
Give an example of an Amphoteric oxide
Al2O3
Does SiO2 react with an acid or base ?
Base
(Doesn’t react with acid)
Does P4O10 react with an acid or base ?
Base
(Doesn’t react with acid)
Does SO2 react with an acid or base ?
Base
(Doesn’t react with acid)
Does SO3 react with an acid or base ?
Base
(Doesn’t react with acid)
What ion does Al2O3 produce when it reacts with a base ?
[Al(OH)4]-
What ion does SiO2 produce when it reacts with a base ?
SiO32-
What ion does P4O10 produce when it reacts with a base ?
PO43-
What ion does SO2 produce when it reacts with a base ?
SO32-
What ion does SO3 produce when it reacts with a base ?
SO42-
What is formed when a basic oxide reacts with an acidic oxide
A salt
What is the general formula of a metal oxide and water
Metal oxide + water —> metal hydroxide
What is the equation for when Na2O reacts with P4O10, and state what type of reaction this is
6Na2O + P4O10 —> 4Na3PO4
Acid-Base reaction
What is the charge of the PO4 ion
PO₄³⁻
What is the charge of the NO3 ion
NO₃⁻
What does the reaction between an acidic oxide and a base form
A salt and water
What does the reaction between an basic oxide and an acid form
A salt and water
When C2O42- acts as a bidentate ligand in a complex, which oxygen forms the coordinate bond
The oxygen with the negative charge
Write the equation for the reaction between Al2O3 in HCl and in excess aqueous NaOH
Al2O3 + 6HCl —> 2AlCl3 + 3H2O
Al2O3 + 2NaOH + 3H2O —-> 2NaAl(OH)4
Write an equation for the reaction between silicon dioxide and an excess of aqueous sodium hydroxide
SiO2 + 2NaOH —-> Na2SiO3 + H2O
Why is the intermediate formed in a 2 step catalysis reaction just as effective as the original catalyst
The steps can occur in any order
(e.g. Fe3+ is just as good of a catalyst as Fe2+ between S2O82- and 2I-)