The Oxides of Period 3 Elements Flashcards

1
Q

Give the equation when oxygen reacts with sodium,magnesium and aluminium and state what type of oxides are formed

A

4Na+O2->2Na2O ionic oxide

2Mg+O2->2Mgo ionic oxide

4Al+3O2->2Al2O3 mostly ionic/covalent

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2
Q

Give the equations when phosphorus,sulphur and silicon react with oxygen

A

Si+O2->SiO2
S+O2->SO2
P4+5O2->P4O10

Molecular covalent oxides are produced

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3
Q

Why is melting point of the oxides high and why do magnesium and aluminium oxide have a higher melting point than sodium oxide

A

They are ionic so they contain electrostatic forces of attraction and aluminium and magnesium have a higher charge than sodium

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4
Q

Despite being covalent why does silicon dioxide have a high melting point

A

They have a giant covalent structure and their are a lot of strong covalent bonds between the atoms in which a lot of energy is need to break

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5
Q

Why is the melting points for p4O10 and So3 low

A

As they are molecular covalent and the only intermolecular forces that exist between them are van der waals

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6
Q

Why is the melting point of P4O10 higher than So3

A

As it’s a larger molecule and so it has stronger van der waals forces

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7
Q

What happens when ionic oxides react with water and what does it mean

A

They produce hydroxide ions and so they act as bases they have o2- ions

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8
Q

What happens when covalent oxides react with water

A

They release H+ ions as well as producing a hydroxide and so are acidic

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9
Q

What it meant by amphoteric

A

That the compound can behave as either an acid or base

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10
Q

Give the equations for the reactions with sodium with water and acids and give the Ph when it reacts with water

(Same with mgo)

A

Na2O +H2O->2NaOH

Na2O+2H+->2Na+. H20

Ph 14

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11
Q

Give the ph when Mgo reacts with water

A

Ph is 9

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12
Q

What type of oxide is aluminium and what does it mean and state why it doesn’t dissolve in water and give the ph and equations

A

It’s an amphoteric oxide and it’s insoluble in water meaningful dissolves in both acid and alkalis

Al2O3 +6HCL->2AlXl

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13
Q

Why can’t silicon oxide react with water,state what it can react with and give the ph

A

Ph=7
It’s insoluble in water it dissolves in hot concentrated alkalis

SiO2 +2OH-> SIO3(2-) +H20

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14
Q

What type of oxide is phosphorus oxide and state what it reacts with as well as giving the ph and equations

A

P4O10 +6H20-> 4H3PO4

Ph= 3

P4O10+12OH- ->4PO4 (-3) +6H20

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15
Q

Give the equations when So2 and So3 react with water and alkalis and give the ph

A

So2 +H20->H2SO3 ph= 2
So3 +h20 ->H2SO4 ph=1

So2+ 2OH- -> SO3(2-)+H2O

So+2OH- -> SO4 (2-)

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16
Q

What is an issue with So2

A

It’s harmful as it dissolves producing acid rain

17
Q

Why can sodium,magnesium,aluminium and silicon reduce water

A

They are more electropositive than hydrogen so they can reduce it

18
Q

What happens when sodium reacts with water and give the ph of the solution formed

A

It reacts vigorously with water and the solution has a ph of 14

2Na +2H20->2NaOH+H2

19
Q

What happens when Mg reacts with steam and give the ph of the solution formed

A

Mg+H20->MgO+H2

Ph is slightly basic with ph of 9

20
Q

State the trend in reactivity to water from na to si

A

Reactivity towards water decreases

21
Q

State the reactivity to water from P to Cl

A

It increases

22
Q

What colour is produced with sodium is burnt

A

It burns with a yellow flame to produce a white solid

23
Q

What colour is produced when Mg,al,si and P are burned

A

A white flame and solid white smoke

24
Q

What is produced when sulfur is burned

A

A blue flame and choking gas

25
Q

What is produced when period 3 metals react with

Water

A

Oxide and hydrogen

Mg +h20->Mgo+H2

26
Q

State how you would prove compounds contain ions

A

Melt the solids and show that they conduct electricity

27
Q

Why is sodium placed under water and phosphorus placed under water

A

To

Stop them reacting with air

28
Q

Give the equation for when aluminium oxide acts as a base

A

Al2O3+2Naoh->4Na3Po4+6H2o