# You are a compound in the laboratory. You find that it is made up of carbon, hydrogen, and oxygen in a ratio of two hydrogen atoms for each carbon atom. How will you classify the compound?

Mar 11, 2018

It's a carbohydrate! Well funnily the way the question is phrased: you are a carbohydrate, since you are the compound

#### Explanation:

The question states the compound is made up of only carbon, oxygen and hydrogen, therefore it narrows it down to Lipids or carbohydrates as a macromolecule choice.
Carbohydrates have a ratio of 2 hydrogen atoms for each oxygen and carbon atom.
Lipids do not have a set ratio like carbohydrates do.

Mar 12, 2018

You got me. Without more info, you could be talking about any of these four... and they even have exceptions that are due to degrees of unsaturation...

SOME carbohydrates, SATURATED esters, SATURATED carboxylic acids, or SATURATED ketone... but there are always exceptions!

$\text{Carbohydrate": "C"_n"H"_(2n)"O}$ general formula, does NOT always hold!

${\text{Saturated Ester": "H"_3"C"("CH"_2)_n"COO"("CH"_2)_n"CH}}_{3}$ general formula, does NOT always hold!

$\text{Saturated Carboxylic acid": "H"_3"C"("CH"_2)_n"COOH}$ general formula

${\text{Saturated Ketone": "H"_3"C"("CH"_2)_n"CO"("CH"_2)_n"CH}}_{3}$ general formula

Any of these have a $\text{C":"H}$ ratio of $1 : 2$. I've listed some examples below.

CARBOHYDRATE EXAMPLES

• glucose - matches description (${\text{C"_6"H"_12"O}}_{6}$)
• $\textcolor{red}{\text{sucrose}}$ - does NOT match description (${\text{C"_12"H"_22"O}}_{11}$)

ESTER EXAMPLES

• ethyl acetate (${\text{C"_4"H"_8"O}}_{2}$)
• methyl acetate (${\text{C"_3"H"_6"O}}_{2}$)
• $\textcolor{red}{\text{methyl acrylate}}$ - does NOT match description (${\text{C"_4"H"_6"O}}_{2}$)

CARBOXYLIC ACID EXAMPLES

• acetic acid (${\text{C"_2"H"_4"O}}_{2}$)
• formic acid (${\text{CH"_2"O}}_{2}$)
• $\textcolor{red}{\text{maleic acid}}$ - does NOT match description (${\text{C"_4"H"_4"O}}_{4}$)

KETONE EXAMPLES

• ethyl methyl ketone ($\text{C"_4"H"_8"O}$)
• $\textcolor{red}{\text{methyl vinyl ketone}}$ - does NOT match description ($\text{C"_4"H"_6"O}$)