Alkenes And Alkanes

Question 1

What is the homologous group for alkanes?
What is the functional group?
What is the general formula?

Answer 1

Alkanes
None
C(n)h(2n+2)

Question 2

What is the HG for the alkenes?
What is the functional group?
Formula?

Answer 2

Alkenes
c=c double bond
C(n)h(2n)

Question 3

What are structural isomers?

Answer 3

Molecules with the same molecular formulae but different structural formulae
I.e butane and methyl-propane

Question 4

How do the melting and boiling points of branched chain alkanes differ?
Why?

Answer 4

Slightly lower melting and boiling points.

Shape means they don’t pack together well= weaker intermolecular forces

Question 5

What are the reactions of alkanes?

Answer 5

1. Combustion with oxygen

2. substitution with chlorine and bromine-needs UV light

Question 6

Are the alkenes saturated or unsaturated?

Answer 6

They are unsaturated as they contain a c=c double bond

Question 7

Are alkenes more or less reactive than the alkanes?

Answer 7

More as they have a functional group

Question 8

What’re the reactions of the alkenes?

Answer 8

1. Combustion - sooty flame(incomplete combustion) because higher proportion of carbon in the molecule
2. Addition - the double bond breaks, allowing other atoms to join

Question 9

Propene + h2?

Answer 9

Propane(hydrogenated)

Question 10

What conditions are needed for the hydrogenation of propene?

Answer 10

150 degrees c

Nickel catalyst

Question 11

Ethene + water?

Answer 11

Ethanol ch3ch2(oh)
This is hydration

Question 12

What conditions are needed for hydration reactions?

Answer 12

300 degrees c
60 ATM
phosphoric acid