Networks And Nanomaterials

Question 1

What is an allotrope?

Answer 1

Different form of the same element, eg graphite diamond

Question 2

Why are Covalent network lattices giant molecules?

Answer 2

No individual molecules exist, it is simply countless atoms covalently bonded. forming a 3d network lattice

Question 3

What is the mohs scale?

Answer 3

Scale measures things in order of hardness. Diamond is 10

able to scratch all surfaces

Question 4

What is an example excluding diamond that is a covalent network lattice?

Answer 4

Silicon dioxide, eg sand

Question 5

Properties of Covalent Network Lattices, short explanation of why

Answer 5

VERY hard- strong covalent bonding exists through crystal structure
High b and m point- Strong covalent bonding holds it together
Do not conduct heat or electricity- No free ions or electrons
BRITLLE- When covalent bonds break, the crystal is distorted and it shatters
Chemically Inert- No outer shell electrons to react
Insoluble in water and most other solvents

Question 6

what are covalent layer lattices?

Answer 6

Countless atoms held covalently together in planes

Layers held together with weak dispersion forces

Question 7

What is graphite?

Answer 7

Covalent layer lattice, 
Oily black solid with mettalic sheen
Allotrope of carbon
Layers of hexagonal rings, with 3 covalent bonds, spare electrons are delocalised and holds layers together
CAN CONDUCT

Question 8

Whats a buckyball?

Answer 8

Cage like molecules, C60- alternating hexagonal and pentagonal rings

Question 9

Properties of buckyballs

Answer 9

Solid at room temp
Soft and resistant to collision
Low m p

Question 10

What is Insoluble in water but soluble in methyl benzene?

Answer 10

Buckyballs

Question 11

What are the conduction properties of buckyballs?

Answer 11

Insulator, super conductor, conductor

Question 12

What are nano tubes?

Answer 12

Flat sheets of carbon wrapped up , similir to graphite in a cylinder
Uses include a space elevator and water filtration

Question 13

What is graphene?

Answer 13

Flat layer of carbon, one atom thick, with remarkable properties. Extremely strong, best conductor there is for heat AND electricity and also more strong and light and flexible than steel

Question 14

What is a covalent molecular substance?

describe regular properties.

Answer 14

Substance of covalent molecules held together with weal dispersion, and dipole dipole/hydrogen bonding
Low b p and soft

Question 15

Are covalent layer lattices hard or soft?

Answer 15

soft