Bonding and Structure

Question 1

Vaporisation

Answer 1

The change from liquid to gas

Question 2

Evaporation

Answer 2

Vaporization from the surface of a liquid

Question 3

Boiling

Answer 3

Vaporization from within as well as from the surface of a liquid

Question 4

Condensation

Answer 4

The change from gas to liquid

Question 5

Sublimation

Answer 5

The change from solid to gas

Question 6

Desposition

Answer 6

The change from gas to solid

Question 7

Ionic bonds

Answer 7

Metal transfers electrons from its outer shell to non-metals. The atoms become oppositely charged ions. This produces a strong electrostatic attraction between ions.

Question 8

Giant ionic lattice

Answer 8

Ions are arranged in a regular way, where the positive ions are strongly attracted to negative ions by electrostatic forces in all directions.

Question 9

Physical properties of ionic compounds

Answer 9

High melting and melting points due to needing a lot of energy to overcome strong electrostatic forces.
Conducts electricity in solution or molten not in solid as charge can flow through free ions.

Question 10

Covalent bonding

Answer 10

When atoms share pairs of electrons. This happens between non-metal atoms and the bonds are very strong.

Question 11

What are examples of simple covalent molecules?
What state can they be in?
Low or high m and b points?

Answer 11

Carbon dioxide, water and methane
Solids, liquids or gases
Low melting and boiling points

Question 12

What is diamond?

Answer 12

Giant covalent structure

Question 13

What is silicon dioxide?

Answer 13

Giant covalent structure

Question 14

What are polymers?

Answer 14

Very large molecules and are covalently bonded.

Question 15

What is a simple molecule structure?
What are the bonds?
What are 2 properties?

Answer 15

A few atoms joined together by strong covalent bonds.
Both elements and compounds.
Held together by weak intermolecular forces.
Low melting and boiling points.
Can’t conduct electricity.

Question 16

Polar covalent bonds

Answer 16

Formed when shared pair of electrons aren’t shared equally. This is due to one of the elements being more electronegative than the other.

Question 17

Non-polar covalent bonds

Answer 17

Formed when there is equal sharing of electrons. They do not react electrostatic like water does. Has relatively no electronegative difference.

Question 18

What is fullerene made of?

Answer 18

Carbon

Question 19

Properties of graphene

Answer 19

Strong- presence of strong covalent bonds
Good at conducting electricity- delocalised electrons
Hard to melt- presence of strong covalent bonds.
Easy to see through- Only 1 atom thick.

Question 20

Uses for graphene and fullerenes

Answer 20

New ways of delivering drugs
New composite materials
New electrical wiring
New lubricants

Question 21

Properties of polymers

Answer 21

Chemically unreactive
Solids at room temp
Moulded into shape
Electrical insulators
Strong and hard-wearing
Rigid/ flexible
Resistant to chemicals

Question 22

What is degree of polymerisation?

Answer 22

The average number of mer units in a chain.

Question 23

Addition polymers

Answer 23

Monomers join together to make a polymer and no other substance is formed. Alkenes

Question 24

Condensation polymer

Answer 24

Monomers join together to make a polymer and other small molecules, often water, is given off. Molecules with two functional groups.

Question 25

What are carbon allotropes?

Answer 25

Different physical forms of carbon.

Question 26

What are 4 properties of Diamonds

Answer 26

Highest hardness and thermal conductivity Rigid lattice- prevents contamination Don't react with chemical reagents Covalently bonded in a tetrahedron allowing zero bond-angle strain.

Question 27

What are industrial uses for diamond?

Answer 27

Cutting Drilling Grinding Polishing

Question 28

What are 5 physical properties of diamond?

Answer 28

Solid colourless and transparent Melting point above 350 Reflects the light, being shiny Insoluble in all dissolves Electric insulator

Question 29

Structure of Graphite

Answer 29

Each atom is joined by three other atoms by covalent bonds. Carbon atoms are layered in a hexagonal lattice.

Question 30

What are the different forms of graphite?

Answer 30

Alpha ( hexagonal) Beta ( rhombohedral)

Question 31

What are 9 physical properties of graphite?

Answer 31

Solid, opaque, black-grey, glossy, greasy Melting point above 350 Harder than water but lighter than diamond Insoluble in all dissolves Low- hardness Electric conductor - due to vast electron delocalisation within carbon layers Plans slide over each other Self lubricating and dry lubricating Weak intermolecular forces between layers

Question 32

Why does metallic bonding occur?

Answer 32

Around positive metal ions there is a sea of delocalised electrons. The negative and positive attract.

Question 33

What would determine the strength of a metallic bond?

Answer 33

Number of protons (the more protons the stronger the bond) Number of delocalised electrons per atom (the more the stronger) Size of the ion (the smaller the ion; the stronger the bond)

Question 34

What is denser ionic lattices or metallic lattices?

Answer 34

Metallic lattices

Question 35

Properties of metal

Answer 35

Malleable Ductile High melting and boiling points Good conductors of heat and electricity because delocalised electrons can carry a charge through the metal.

Question 36

What is an alloy?

Answer 36

Pure copper, gold and aluminium are mixed with other metals which is harder as they are soft metals to start with.

Question 37

What are 2 properties of nanoparticles?

Answer 37

High surface area to volume ratio a greater proportion of particles exposed on the surface. Highly reactive- smaller quantities are needed to be more effective than materials with normal particle sizes.

Question 38

What are 6 things nanoparticles are used for?

Answer 38

Medicine Electronics Deodorants Cosmetics Sun creams Catalysts

Question 39

What do silver nanoparticles do?

Answer 39

Kill bacteria so are woven into thread of socks. Help decompose materials in sewage works.

Question 40

How does a metal conduct thermal energy?

Answer 40

Thermal energy is transferred by delocalised electrons.

Question 41

Why does mixing iron with other metals make alloys that are harder?

Answer 41

The alloy has different sized atoms so the layers are distorted so they can't slide over each other easily.