Macromolecular substances

Question 1

What is a macromolecule?

Answer 1

they are massive, covalently bonded molecules, which consist of thousands of atoms.

Question 2

What are the 3 types of macromolecules?

Answer 2

1. regular, repeating, 3D lattice of long chains, of thusands of atoms
2. regular, repeating, 3D lattice of two dimensional sheets, made out of thousands of atoms.
3. regular, repeating, 3D lattice of 3D network made out of thousands of toms.

Question 3

What is a molecular lattice?

Answer 3

When a lattice is made out of smaller molecules, fewer than 1000 also.

Question 4

Explain how macromolecules made out of chains, or sheets, are held together.

Answer 4

They are held together by intermolecular forces.

Question 5

explain how macromolecules made out of 3D networks, are held together.

Answer 5

There are NO intermolecular forces, because its all just one big covalently bonded molecule.

Therefore, they are held together by covalent bonds only.

Question 6

State the three main macromolecules you need to know for A level.

Answer 6

Diamond, graphite, and silicon dioxide.

Question 7

Describe the structure of diamond.

Answer 7

Is a macromolecular 3D, repeating lattice, which consists of covalent bonds between carbon atoms. One carbon atom, is bonded to 4 other carbon atoms, and so on.

Question 8

describe the structure of graphite.

Answer 8

Graphite contains graphene, which is a 2D, regularly repeating sheet, which consists of covalent bonds between carbon atoms.
Each carbon atom is bonded to 3 other carbon atoms.

These 2D sheets, are held together by intermolecular forces ( wan der waals forces), to make graphite.

Question 9

What is an allotrope?

Answer 9

The allotropes of an element, are the different structures that can form, when atoms of that element can bond together.

Question 10

Explain why diamond does not conduct electricity, but graphite does.

Answer 10

Because graphite has delocalised electrons, which can move freely, and conduct a charge.

Diamnd does not.

Question 11

Explain why diamond is much more harder than graphite.

Answer 11

Because if we want to break up diamond, we need to break its strong covalent bonds.

Whereas, to separate graphite, we only need to beak the weak intermolecular forces.

Question 12

Explain why all macromolecules have extremely hugh meltin and boiling points.

Answer 12

Because it requires alot of energy to break the covalent bonds.

Question 13

state wich type of structure, the following crystals contain:
diamond
graphite
ice
iodine
magnesium
sodium chloride.

Answer 13

diamond: macromolecular ( 3D network).
graphite: macromolecular ( 2D sheets).
ice: moelcular
iodine: molecular
magnesium: metalic
sodium chloride: ionic