Alkene Facts for Kids

In organic chemistry, an alkene is a special type of chemical compound. It's also called an olefin. What makes an alkene special is that it has at least one carbon atom connected to another carbon atom by a double bond. Think of it like two hands holding each other very strongly.

The simplest alkenes have just one double bond. They don't have rings or other special parts. These are hydrocarbons, meaning they are made only of hydrogen and carbon. Their general formula is C_nH_2n. This means if there are 'n' carbon atoms, there will be '2n' hydrogen atoms.

Even though some drawings of other chemicals called 'aromatic compounds' might look like alkenes, they are actually quite different. They are not considered alkenes.

The double bond in alkenes makes them more reactive than other similar compounds. This is because they are "unsaturated," meaning they have room to add more atoms. For example, an alkene can easily react with bromine, which makes the bromine lose its color. The names of all alkenes always end with "-ene."

What are Some Alkenes?
How Alkenes Look and Feel
Why Alkenes Are Not Used as Fuel
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What are Some Alkenes?

Here is a list of the first few alkenes. They are named based on how many carbon atoms they have:

Ethene (C₂H₄) - This is the simplest alkene, with two carbon atoms.
Propene (C₃H₆) - Has three carbon atoms.
Butene (C₄H₈) - Has four carbon atoms.
Pentene (C₅H₁₀) - Has five carbon atoms.
Hexene (C₆H₁₂) - Has six carbon atoms.
Heptene (C₇H₁₄) - Has seven carbon atoms.
Octene (C₈H₁₆) - Has eight carbon atoms.
Nonene (C₉H₁₈) - Has nine carbon atoms.
Decene (C₁₀H₂₀) - Has ten carbon atoms.
Undecene (C₁₁H₂₂) - Has eleven carbon atoms.
Dodecene (C₁₂H₂₄) - Has twelve carbon atoms.
Tridecene (C₁₃H₂₆) - Has thirteen carbon atoms.
Tetradecene (C₁₄H₂₈) - Has fourteen carbon atoms.
Pentadecene (C₁₅H₃₀) - Has fifteen carbon atoms.
Hexadecene (C₁₆H₃₂) - Has sixteen carbon atoms.
Heptadecene (C₁₇H₃₄) - Has seventeen carbon atoms.

How Alkenes Look and Feel

The way alkenes look and feel is quite similar to alkanes, which are compounds with only single bonds. The main difference is how they react.

The physical state of an alkene (whether it's a gas, liquid, or solid) depends on how many carbon atoms it has.

The simplest alkenes, like ethene, propene, and butene, are gases at room temperature.
Alkenes with about five to sixteen carbon atoms are liquids.
Alkenes with even more carbon atoms are waxy solids.

Why Alkenes Are Not Used as Fuel

Alkenes are generally not used as fuels for a couple of reasons:

They are not very common in nature. Instead, they are often made from other hydrocarbons. These alkenes are then used to create many useful things like plastics, anti-freeze, and other important compounds.
When alkenes burn, they often produce a smoky flame. This happens because they don't burn as completely as some other fuels. This means they release less heat energy and create more pollution.