What is the empirical formula of cellulose?

The empirical formula of cellulose is ##"C"_6"H"_10"O"_5.##

Cellulose is a long-chain polymer of glucose molecules.

The structure of glucose, ##"C"_6"H"_12"O"_6##, is

Two molecules of glucose can condense by splitting out a molecule of water between them to form cellobiose.

This process can be repeated over and over, with the chain getting longer and longer. The resulting chain is called cellulose.

We see that the repeating unit (in brackets) in cellulose has the formula ##"C"_6"H"_10"O"_5##.

We could write the equation for the formation of cellulose as

##underbrace(n"C"_6"H"_12"O"_6)_color(red)("glucose") → underbrace(("C"_6"H"_10"O"_5)_n)_color(red)("cellulose") + n"H"_2"O"##

So the formula of cellulose is ##("C"_6"H"_10"O"_5)_n##.

Its empirical formula is therefore ##"C"_6"H"_10"O"_5##.