SC7a Molecular Compounds

Question 1

properties of simple covalent molecules

Answer 1

weak intermolecular forces need to be overcome; does not need a lot of energy so it has low melting and boiling points
simple molecules have no overall charge and no free electrons so they cannot carry a current.

Question 2

what happens the longer the polymer is and why?

Answer 2

the higher the melting and boiling point because there are more intermolecular forces.​

Question 3

example of polymers?

Answer 3

polystyrene

Question 4

How strong are the forces of attraction between molecules compared to the bonds within molecules? ​

Answer 4

relatively weak

Question 5

Are simple molecules usually good conductors of electricity at room temperature​?

Answer 5

no

Question 6

What is the name for lots of monomers joined together to form large molecular chains? ​

Answer 6

polymers

Question 7

What simple molecule joins to form the large molecule poly(ethene)? ​

Answer 7

ethene

Question 8

Why might simple molecules, such as methane, have low melting points? ​

Answer 8

because they have weak intermolecular forces of attraction between them.

Question 9

Explain why small molecules have a lower melting point than large polymer molecules. (3 marks)

Answer 9

Weak forces of interaction/intermolecular forces between molecules (1) ​
More forces of interaction/intermolecular forces in larger molecules ora (1) ​
More energy is required to break these forces of interaction/intermolecular forces ora (1)