Chemistry Topic 2 - Bonds

Question 1

Disadvantages of dot and cross diagrams?

Answer 1

Dont tell us about the shape of the molecule

Question 2

Advantages of dot and cross diagrams?

Answer 2

Tell us the bonds which are present

Question 3

Advantages of line diagrams?

Answer 3

Tell us about the angles of bonds

Question 4

Disadvantages of line diagrams?

Answer 4

Fail to represent the space in between the atoms
Unable to represent in 3d

Question 5

Advantages of 3d Models?

Answer 5

Show more accurate shapes of molecules and space filled

Question 6

Disadvantages of 3D Models?

Answer 6

Fail to represent distribution of electrons within the molecule

Question 7

Features of covalent bonds?

Answer 7

Very strong and difficult to break but forces between molecules are very weak

Question 8

Features of molecules with simple covalent bonds?

Answer 8

The weak intermolecular forces are easy to overcome than electrostatic attraction found in ionic substances

Question 9

What state are molecules with covalent bonds found at in room temperature?

Answer 9

As liquid or gases

Question 10

Trends in size of molecules with covalent bonds

Answer 10

Intermolecular forces increase and so do there boiling/melting point

Question 11

Why don’t covalent bonds conduct electricity?

Answer 11

Have the same number of protons and electrons

Question 12

Features of polymers?

Answer 12

Due to polymers very large and lots of covalent bonds, the intermolecular forces are much stronger
Melting point is low

Question 13

What are polymers?

Answer 13

Long chain of carbon atoms held together by covalent bonds

Question 14

What are giant covalent structures?

Answer 14

All atoms are bonded together into a large lattice

Question 15

Example of a giant covalent structure?

Answer 15

Diamond
Silicon dioxide
Graphite

Question 16

Physical properties of a giant covalent structure?

Answer 16

Very strong and hard
High melting point

Question 17

Why are diamonds the hardest material known to man?

Answer 17

Billions of covalent bonds need high energy to overcome so a lot of force needed

Question 18

Bonds in graphites and arrangement?

Answer 18

Each carbon is bonded to 3 others arranged in flat sheets of hexagon with high intermolecular forces
The sheets are than layered over each other with weak intermolecular forces to slide over each other

Question 19

Why can graphite conduct electricity?

Answer 19

As they have 3 bonds, they have 1 delocalised electron

Question 20

Features of graphite

Answer 20

Slippery, Conduct electricity, high melting and boiling point

Question 21

What is graphite used for?

Answer 21

Pencil Lead

Question 22

Whats graphene?

Answer 22

Single layer of Graphite

Question 23

Features of graphene?

Answer 23

Very strong covalent bonds
1 atom thick
Very high melting and boiling point (4510)
Conduct electricity

Question 24

Use of graphene?

Answer 24

Used in composites to make materials stronger without making it heavier

Question 25

What are fullerene?

Answer 25

Shaped as either tubes or hollow balls.

Question 26

Who discovered the fullerene?

Answer 26

Buckminsterfullerene

Question 27

Formula for fullerene?

Answer 27

C60

Question 28

Use of fullerenes?

Answer 28

Strengthen material without adding to weight
Deliver drugs to inside of body
Catalyst

Question 29

Shape of metal when solid?

Answer 29

Lattice of positive metal ions surrounded by a sea of delocalized electrons

Question 30

How is a sea of electrons created in a metal lattice?

Answer 30

When metal atoms come together they give up all their outer shell electrons to form a shared group

Question 31

Bonds in metal?

Answer 31

The electron sea and positively charged metal ions are attracted

Question 32

Properties of metals?

Answer 32

High melting points (300oc to 3000oc)
Can conduct electricity even while solid unlike ionic
Electron can carry thermal energy making good conductors of heat
Ductile due to being in layers
Non soluble

Question 33

Metal which has a low melting point?

Answer 33

Mercury has a melting point of 39oC

Question 34

What’s ductile?

Answer 34

Can be bent and formed into different shapes

Question 34

What is one nanometre equivalent to in metres?

Answer 34

1Nm is equal to 1 billionth of a metre

Question 35

What are coarse particles?

Answer 35

Range from 2500 to 1million Nm in size

Question 36

What are coarse particles referred to as?

Answer 36

PM10, meaning particulate matter which is less than 10 micrometres

Question 37

Where atoms found in nanoparticles?

Answer 37

Contained at the surface compared to atoms where they are found inside

Question 37

What are nano particles?

Answer 37

Ranging from 1 to 100Nm

Question 37

What are fine particles

Answer 37

100 to 2500Nm in size, referred to as PM2.5

Question 38

What happens to volume to surface area ratio is a side decrease by 10

Answer 38

Surface area to volume ratio increase by 10

Question 38

Surface area to volume ratio in nano particles?

Answer 38

Have very high surface to volume ratio

Question 38

Rate of reaction of nanoparticles?

Answer 38

Have very high rate of reactions, due to more surface to react with

Question 39

Advantages of using nanoparticles as catalysts?

Answer 39

Have high surface area to volume ratio, meaning a smaller quantity needed

Question 40

Applications of nanoparticles?

Answer 40

Nanoparticles of silver has antibacterial properties
When added to masks or gloves prevent spread of diseases
Drug delivery vehicles

Question 41

Why are nanoparticles not used in medicine?

Answer 41

Not aware of full effects of nanoparticles on human health