1(f, g)

Question 1

Formula and charge of ammonium.

Answer 1

NH4 +

Question 2

Formula and charge of carbonate.

Answer 2

CO3 2-

Question 3

Formula and charge of nitrate.

Answer 3

NO3 -

Question 4

Formula and charge of sulphate.

Answer 4

SO4 2-

Question 5

What is ionic bonding in terms of electrostatic attractions?

Answer 5

Ionic bonding is the strong electrostatic attraction between oppositely charged ions.

Question 6

Why do compounds with giant ionic lattices have high melting and boiling points?(2)

Answer 6

There are many strong ionic bonds/electrostatic attractions between negative and positive ions.
Therefore lots of energy is required to overcome then; hence high melting and boiling points.

Question 7

What is covalent bonding in terms of electrostatic attractions?(2)

Answer 7

A covalent bond is the strong electrostatic attraction between positively charged nuclei and the pair of electrons shared between them.

Question 8

What are substances with simple molecular structures?(3)

Answer 8

Within a bunch of covalent molecules together, there are strong covalent bonds within each molecule, but between the molecules there are weaker intermolecular attractions.
When a substance has molecules with intermolecular forces of attraction between them, they have a simple molecular structure.
Things with simple molecular structures usually have low melting points and boiling points because not that much energy is required to break the weak intermolecular forces of attraction between molecules.

Question 9

Why do the melting and boiling points of substances with simple molecular structure increase with increasing relative molecular mass?(2)

Answer 9

The larger the molecule means that there are more electrons, hence a greater intermolecular force.
A greater force to overcome concludes a higher melting and boiling point.

Question 10

Why do substances with giant covalent structures have high melting and high boiling points?

Answer 10

Giant covalent structures have many strong covalent bonds.
This means that a lot of energy is required to break them, hence high melting and boiling points.

Question 11

How does the structure of diamond influence its physical properties?(3)

Answer 11

Diamond has a very high melting point and boiling point because the carbon-carbon bonds are very strong and each carbon is bonded to four others in a 3D lattice.
Therefore it takes a lot of energy to break these strong covalent bonds, therefore diamond has very high melting and boiling point.
Diamond is also very hard for this same reason

Question 12

How does the structure of graphite influence its physical properties?(4)

Answer 12

Graphite has a layer structure and therefore is a soft material, because the layers can slide.
Graphite still has high melting and boiling point though because the covalent bonds have to be broken.
Graphite also conducts electricity because there is a delocalised electron for every graphite atom.
These delocalised electrons are free to move throughout the layers which allows graphite to conduct electricity.

Question 13

How does the structure of C60 fullerene influence its physical properties?(3)

Answer 13

Fullerene has a lower melting and boiling point than diamond and graphite.
When fullerene is melted, only the weak intermolecular forces of attraction must be broken.
Fullerene also can’t conduct electricity because the free electron can’t move molecule to molecule.