[awesome31312]

3. Alkenes
b) Name these compounds:

Using the steps my teacher taught me

I see a five carbon chain with a double bond, so that's pentene
There's also two methyl branches, so it's dimethyl.

However, this is where it gets tricky. The numbering.

Which way do I number?

2,4-dimethylpent-2-ene
OR
2,4-dimethylpent-3-ene

Which way does the double bond start?

The confusion arises because I don't know which way to number if both methyl branches start at the same number, in this case, two. I'm sorry if it's hard to explain, I'm just seriously confused right now.

[discodermolide]

As far as the double bond goes give it the lowest number and see where it goes.