The Oxides of Period 3 Elements Flashcards Preview

A Level Chemistry Inorganic > The Oxides of Period 3 Elements > Flashcards

Flashcards in The Oxides of Period 3 Elements Deck (28)
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1

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

4Na+O2->2Na2O ionic oxide

2Mg+O2->2Mgo ionic oxide

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

2

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

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

Molecular covalent oxides are produced

3

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

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

4

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

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

5

Why is the melting points for p4O10 and So3 low

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

6

Why is the melting point of P4O10 higher than So3

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

7

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

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

8

What happens when covalent oxides react with water

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

9

What it meant by amphoteric

That the compound can behave as either an acid or base

10

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

(Same with mgo)

Na2O +H2O->2NaOH

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

Ph 14

11

Give the ph when Mgo reacts with water

Ph is 9

12

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

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

Al2O3 +6HCL->2AlXl

13

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

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

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

14

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

P4O10 +6H20-> 4H3PO4

Ph= 3

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

15

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

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


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

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

16

What is an issue with So2

It's harmful as it dissolves producing acid rain

17

Why can sodium,magnesium,aluminium and silicon reduce water

They are more electropositive than hydrogen so they can reduce it

18

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

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

2Na +2H20->2NaOH+H2

19

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

Mg+H20->MgO+H2
Ph is slightly basic with ph of 9

20

State the trend in reactivity to water from na to si

Reactivity towards water decreases

21

State the reactivity to water from P to Cl

It increases

22

What colour is produced with sodium is burnt

It burns with a yellow flame to produce a white solid

23

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

A white flame and solid white smoke

24

What is produced when sulfur is burned

A blue flame and choking gas

25

What is produced when period 3 metals react with
Water

Oxide and hydrogen

Mg +h20->Mgo+H2

26

State how you would prove compounds contain ions

Melt the solids and show that they conduct electricity

27

Why is sodium placed under water and phosphorus placed under water

To
Stop them reacting with air

28

Give the equation for when aluminium oxide acts as a base

Al2O3+2Naoh->4Na3Po4+6H2o