AQA Combined Chemistry 5.2

Question 1

What is the chemical formula of Buckminsterfullerene?

Answer 1

C(60)

Question 2

What element are all fullerenes made from?

Answer 2

Carbon

Question 3

Describe the structure of fullerenes

Answer 3

Mostly hexagonal rings of carbon. Can be spherical or cylindrical in shape

Question 4

Give three examples of giant covalent structures

Answer 4

Diamond, graphite, silicon dioxide

Question 5

What do the following symbols represent?

a) s
b) l
c) g
d) aq

Answer 5

a) solid
b) liquid
c) gas
d) aqueous

Question 6

Do metals have high or low melting points and boiling points?

Answer 6

High melting and boiling points

Question 7

Diamond and graphite are made out of a single element. Name this element.

Answer 7

Carbon

Question 8

Can molecules conduct electricit? Give a reason for your answer

Answer 8

No, because they have no overall electric charge

Question 9

What type of bond exists between metals and non-metals in a compound?

Answer 9

Ionic Bond

Question 10

What is the name for the forces that exist between ions in an ionic bond?

Answer 10

Electrostatic forces

Question 11

What type of bonding exists in metallic elements and alloys?

Answer 11

Metallic bonding

Question 12

In which type of bond are electrons shared?

Answer 12

Covalent bond

Question 13

In which type of bond are electrons transferred?

Answer 13

Ionic bond

Question 14

What type of bond exists in non-metal elements and compounds?

Answer 14

Covalent Bond

Question 15

What is the name for the electrons that are free to flow in metallic bonding?

Answer 15

Delocalised electrons

Question 16

When atoms gain or lose electrons to become ions, they will have the electron structure of what group of elements?

Answer 16

Noble gases

Question 17

Describe how sodium and chloride bond to form sodium chloride

Answer 17

1) The sodium atom loses one electron to become a sodium ion
2) The chlorine atom gains one electron to become a chloride ion
3) The positive sodium ion is attracted to the negative chloride ion to form sodium chloride

Question 18

What charge do metal ions have?

Answer 18

Metal ions are positive

Question 19

What charge do non-metal ions have?

Answer 19

Non-metal ions are negative

Question 20

Small molecules contain what type of bonds?

Answer 20

Covalent bonds

Question 21

Describe the structure and bonding of an ionic compound

Answer 21

a) ionic bonding
b) giant structure of ions
c) lattice structure
d) oppositely charge ions held together by electrostatic forces acting in all directions

Question 22

Why do small molecules usually have relatively low melting and boiling points?

Answer 22

a) they have weak forces between molecules (intermolecular forces)
b) it is the intermolecular forces that are overcome, not the covalent bonds, when the substance boils.

Question 23

What is the relationship between the forces between particles and a substance’s melting and boiling points?

Answer 23

The stronger the forces between particles, the higher the melting and boiling points

Question 24

What charge do the ions of elements in the following groups have?:

a) Group 1
b) Group 2
c) Group 6
d) Group 7

Answer 24

a) +
b) 2+
c) 2-
d) -

Question 25

Describe the structure and bonding in a metal

Answer 25

a) metallic bonding b) strong metallic bonds c) giant structure of metal atoms in regular pattern d) outer shell electrons are delocalised

Question 26

Why do molten or aqueous solutions of ionc compounds conduct electricity?

Answer 26

Ions are free to move so charge can flow

Question 27

What are the limitations of the following diagrams to represent ionic structures? a) dot and cross b) ball and stick

Answer 27

a) dot and cross - doesn't show the structure of the ionic compound, the size or arrangement of ions b) ball and stick - suggests gap between ions which aren't in fact there

Question 28

Why do ionic compounds have high melting and boiling points?

Answer 28

Because a lot of energy is needed to break the many strong bonds

Question 29

What type of bonds exist in large molecules, such as plymers?

Answer 29

Covalent bonds

Question 30

Describe how the arrangement of atoms makes pure metals soft

Answer 30

a) atoms arranged in layers | b) layers slide easily over each other

Question 31

What are the limitations of using the particle models below to represent solids, liquids and gases?

Answer 31

a) no forces between the particles are shown in the diagram b) all particles are represented by spheres c) all the spheres are solid and inelastic

Question 32

What state are most polymers at room temperature? Why?

Answer 32

a) solid | b) because they are large molecules, with strong intermolecular forces, hence relatively high melting and boiling points

Question 33

What bonds must be overcome in order to melt or boil giant covalent structures?

Answer 33

The strong covalent bonds between the atoms

Question 34

Descrobe the structure and bonding of Diamond

Answer 34

a) giant covalent structure | b) each crbon forms four covalent bonds with other carbon atoms

Question 35

Describe the properties of Diamond

Answer 35

a) hard b) very high melting point c) doesn't conduct electricity

Question 36

What happens to the size of intermolecular forces as the size of molecules increase?

Answer 36

The size of intermolecular forces increase (hence higher melting and boiling points for larger molecules)

Question 37

Why are metals good conductors of heat and electricity?

Answer 37

They have delocalised electrons that can carry the charge or transfer energy

Question 38

What are cylindrical fullerenes called and why are they useful?

Answer 38

a) nanotubes | b) they have a high length to diameter ratio making them useful for nanotechnology, electronics and materials

Question 39

Describe how the arrangement of atoms in an alloy makes alloys harder than pure metal

Answer 39

a) different sized atoms b) layers disorted c) atoms can't easily slide over each other

Question 40

Describe the structure and bonding of Graphite

Answer 40

a) giant covalent structure b) each carbon forms three covalent bonds with other carbon atoms c) forms layers of hexagonal rings d) no covalent bonds between layers e) one electron from each carbon atom is delocalised

Question 41

What is graphene?

Answer 41

A single layer of graphite

Question 42

Name two uses of graphene

Answer 42

Used in electronics and composites