Here's why:

* Glucose is a molecular compound: Glucose is formed by the covalent bonding of carbon, hydrogen, and oxygen atoms.

* Molecules are the smallest unit of a compound: A molecule of glucose contains 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms (C6H12O6).

* Representative particles are used in stoichiometry: When performing calculations in chemistry, we use representative particles to represent the amount of substance. For molecular compounds, the representative particle is the molecule.

So, when talking about glucose in a chemical context, we're referring to individual molecules of glucose.