Properties of Hydrocarbons

Question 1

What’s a common relationship between alkanes, alkenes and alkynes and their melting points?

and Why?

Answer 1

The longer the carbon chain, the higher the melting and boiling point.

Due to the increase of dispersion forces needed to be broken with heat

Question 2

What’s a common relationship between alkanes, alkenes and alkynes and their insolubility?

and Why?

Answer 2

The longer the carbon chain, the more insoluble they are
Due to the more and more non-polar they become (ends have a far distance)

Question 3

Which hydrocarbon has the highest melting and boiling points?

and Why?

Answer 3

Alkynes
Due to their more linear structure, the dispersion forces are more tightly packed

Question 4

Which hydrocarbon has the lowest melting and boiling points?

and Why?

Answer 4

Alkenes
Due to they have 2 less hydrogens than alkanes, so less electrons and so weaker dispersion forces

Question 5

Does alcohol have a high melting and boiling point

and Why?

Answer 5

Yes due to their strong hydrogen bonding

Question 6

Why are hydrocarbons not soluble in general?

Answer 6

Non-polar

Question 7

What makes something soluble?

Answer 7

If they are polar like water

Question 8

Are alcohols soluble?

what are the exceptions & why?

Answer 8

Yes, but only ones with small carbon chains are soluble
Because they are polar

Question 9

What do alkanes and alkenes have in common?

Answer 9

They are mostly gases or liquids

Question 10

What do alkynes and alcohol have in common?

Answer 10

They are mostly liquids