Structure 2.4

Question 1

Alloy properties

Answer 1

Lower melting points, less malleable/ductile, harder, less directional bonding

Question 1

Alloys

Answer 1

A mixture of more than one metal

Question 2

Polymer

Answer 2

A repeating chain of monomers held together by covalent bonds

Question 3

Monomer

Answer 3

Individual repeating units in a polymer

Question 4

Monomers joint in addition reactions

Answer 4

Addition polymer and condensation reactions - don’t form byproducts

Question 5

Thermoplastics

Answer 5

Soften when heated and harden when cooled, recyclable

Question 6

Thermosetting plastics

Answer 6

Change irreversibly into hardened thermosets and cannot be recycled

Question 7

Elastomers

Answer 7

Polymers that are flexible and can be reformed under a force but will return to the original shape when stress is released

Question 8

Bonding triangle

Answer 8

Shows the three extreme types of bonding plotted against the difference in electronegativity and the change in electronegativity

Question 9

Ionic bond

Answer 9

Electrostatic attractions between two oppositely charged ions

Question 10

Covalent bond

Answer 10

The electrostatic attraction between the nuclei of two atoms and their valence electrons, sharing of electrons

Question 11

Metallic bonds

Answer 11

The electrostatic attraction between the cations and sea of delocalised valence electrons

Question 12

When does a solid melt?

Answer 12

When attractive forces between particles are overcome and particles are free to move

Question 13

What is melting point influenced by?

Answer 13

The way in which particles pack in the solid state

Question 14

Ionic compounds conductivity

Answer 14

Don’t conduct in solid state but conduct when molten or in aqueous liquid

Question 15

Why do ionic compounds (molten/in aqeous) decompose when conducting?

Answer 15

As conductivity is due to movement of electrons

Question 16

Conductivity of allotropes of non metals

Answer 16

Usually good as they have delocalised electrons

Question 17

Elasticity

Answer 17

The ability of a material to resist a distorting influence and return to original when force is removed

Question 18

Metals elasticity

Answer 18

Elastic as atoms can easily slide over each other in the lattice

Question 19

Polymer elasticity

Answer 19

Can be stretched without being permanently broken so are elastic

Question 20

Covalent solid brittleness

Answer 20

Very brittle as bonds cannot be reformed once broken

Question 21

Metals brittleness

Answer 21

Very malleable as layers of atoms can slide over each other

Question 22

Ionic solid brittleness

Answer 22

Very brittle as ionic lattice breaks without being deformed when sufficient force is applied

Question 23

Addition polymers

Answer 23

Formed from alkenes and no other product are produced, a carbon to carbon double bond is broken

Question 24

100% atom economy

Answer 24

All reactant becomes product

Question 25

Condensation reaction

Answer 25

Water will be produced in addition to the condensation product

Question 26

What is needed to form a condensation polymer?

Answer 26

Two functional groups (can be same or different) so that once the condensation product in formed, it can continue reacting with two functional groups

Question 27

Ester link

Answer 27

One monomer has two carboxlic acid groups, one monomer has two alcohol groups (-COOH, -OH)

Question 28

Polyester

Answer 28

A polyester is made by a reaction involving an acid with two carboxlic groups, and an alcohol with two alcohol groups.

Question 29

What happens when a monomer with two carboxylix acid and one monomer with two amine groups react?

Answer 29

A polyamide is formed

Question 30

Aminde link

Answer 30

When a monomer with two carboxylix acid and one monomer with two amine group react, an aminde link forms (-COOH, -NH2)

Question 31

Polyamide can also be formed...

Answer 31

By condensing amines with either dicarboxlyic acids or with diacyl chlorides

Question 32

Kevlar

Answer 32

Condensation polymer and also example of a polyamide

Question 33

Why is kevlar so strong?

Answer 33

Because it consists of rigid rod shaped molecules that are cross linked by intramolecular hydrogen bonding between the chains

Question 34

When does kevlar lose its protective properties?

Answer 34

In concentrated sulfric acid solution, the O and N atoms in the amide linkage become prononated and break down

Question 35

Biological macromolecules

Answer 35

Condensation polymers

Question 36

Amino acids

Answer 36

Building blocks of proteins, have a carboxyl group and an amino group bonded to the same carbon atom

Question 37

Peptide bond

Answer 37

Amide bond amino acids form

Question 38

Polysaccharides

Answer 38

Many sugar units condensed together

Question 39

Hydrolysis

Answer 39

Reverse reaction of condensation

Question 40

Alloy

Answer 40

Mixture of more than one metal

Question 41

Properties of an alloy

Answer 41

Lower melting point, harder, more brittle

Question 42

What can polymers form and how?

Answer 42

Addition polymers through addition reactions, condensation polymers and polysaccardies through condensation reactions

Question 43

Thermoplastics

Answer 43

Can be remoulded when heated

Question 44

Thermosetting

Answer 44

Changes irreversibly in soft solid/viscous state

Question 45

Elastomers

Answer 45

Flexible polymers that can return to original shape

Question 46

Delocalised pi electron

Answer 46

An electron shared between two or more nuclei, found in all resonance structures