Polymers and Giant Covalent Structures

Question 1

What is a polymer?

Answer 1

A long molecule formed by linking many small units together that have repeating sections

Polymers can contain thousands or millions of atoms.

Question 2

What type of bond joins the atoms in a polymer?

Answer 2

Strong covalent bonds

This strong bonding is crucial for the stability of the polymer structure.

Question 3

What is the repeating section in a polymer called?

Answer 3

Repeating unit

The repeating unit is often represented in brackets in molecular formulas.

Question 4

How do you find the molecular formula of a polymer?

Answer 4

Write down the molecular formula of the repeating unit in brackets and put an ‘n’ outside

‘n’ represents the number of times the repeating unit is repeated.

Question 5

What is the molecular formula of poly(ethene)?

Answer 5

(C2H4)n

This formula indicates that the repeating unit is C2H4 and is repeated n times.

Question 6

Why are most polymers solid at room temperature?

Answer 6

The intermolecular forces between polymer molecules are larger than those between simple covalent molecules

More energy is needed to break these forces.

Question 7

How do the boiling points of polymers compare to ionic or giant molecular compounds?

Answer 7

Polymers generally have lower boiling points than ionic or giant molecular compounds

This is due to weaker intermolecular forces compared to ionic or covalent bonds.

Question 8

What characterizes giant covalent structures?

Answer 8

All atoms are bonded to each other by strong covalent bonds

This results in very high melting and boiling points.

Question 9

Do giant covalent structures conduct electricity?

Answer 9

No, they do not conduct electricity, not even when molten, except for some exceptions like graphite

Graphite can conduct electricity due to its delocalized electrons.

Question 10

What are the main examples of giant covalent structures?

Answer 10

• Diamond
• Graphite
• Silicon dioxide (silica)

These structures are primarily composed of carbon atoms.

Question 11

How does each carbon atom behave in diamond?

Answer 11

Each carbon atom forms four covalent bonds in a rigid giant covalent structure

This structure contributes to diamond’s hardness.

Question 12

How does each carbon atom behave in graphite?

Answer 12

Each carbon atom forms three covalent bonds to create layers of hexagons with one delocalized electron

The delocalized electron allows graphite to conduct electricity.

Question 13

What is silicon dioxide also known as?

Answer 13

Silica

Silica is a common component of sand and has a giant covalent structure.