Alkanes and Alkenes

Question 1

What is an alkane?

Answer 1

A homologous series of hydrocarbons with the general formula CₙH₂ₙ₊₂

Question 2

What are the first 4 alkanes?

Answer 2

Methane (CH4), Ethane (C2H6), Propane (C3H8), Butane (C4H10).

Question 3

Are alkanes saturated or unsaturated?

Answer 3

Alkanes are saturated - the atoms have formed bonds with as many other atoms as they can.

Question 4

What is an alkene?

Answer 4

A homologous series of hydrocarbons with the general formula CₙH₂ₙ

Question 5

What makes alkenes differ from alkanes?

Answer 5

Alkenes have a double carbon bond (C=C).

Question 6

Are alkenes saturated or unsaturated?

Answer 6

Alkenes are unsaturated - the double bond can open up, so not all possible bonds are formed.

Question 7

What are the first 3 alkenes?

Answer 7

Ethene (C2H4), Propene (C3H6), Butene (C4H8).

Question 8

What are the two different names of Butene?

Answer 8

But-1-ene (double bond on the end like the rest), and But-2-ene (double bond in the middle).

Question 9

How can you test for an alkene using bromine water?

Answer 9

Shake alkene and bromine water together. If an alkene is present, it liquid will turn from orange to colourless. This is an addition reaction, where the bromine takes the place of hydrogen.