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How can you recognize alkenes?

Answer 1

Skylar Alexander

Put simply, any hydrocarbon with at least one double-bonded carbon is considered an alkene.

Let's look at a couple different hydrocarbons and see if we can classify them.

Hydrocarbon 1:

Hydrocarbon 2:

Hydrocarbon 3:

We'll look at Hydrocarbon 1 first. It's got four single-bonded carbons, so this guy is known as butane. Butane would be considered an alkane, not an alkene, since it has no double-bonded carbons.

Hydrocarbon 2 has two carbons, and one double-bond. We call this guy ethene, or ethylene. You can probably guess that ethene is an alkene, due to the "ene" and you'd be correct.

Hydrocarbon 3 has three carbons, and there is one double bond. We'd call this guy 1-propene, or propylene, and it is in fact an alkene.

So that's essentially how you do it: look for double-bonded carbons. If there is at least one, the molecule is considered an alkene.

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Answer 2

Christian Anderson

Alkenes are recognized by the presence of a carbon-carbon double bond.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.