Do all organic molecules contain carbon, hydrogen, and oxygen?


No, but they all contain carbon and hydrogen.


Almost all organic molecules contain carbon and hydrogen, and many contain other elements as well.

For example, ethane is #"CH"_3"CH"_3#. It contains only carbon and hydrogen.

Ethanol is #"CH"_3"CH"_2"OH"#. It contains oxygen as well.

Glycine is #"H"_2"NCH"_2"COOH"#. This one adds nitrogen.

There are many more examples, but all contain carbon and hydrogen.

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