To calculate the mass of one mole of acetic acid (CH3COOH), we need to add the atomic masses of each atom in the molecule.

Here's the breakdown of the atomic masses:

- Carbon (C): 12.01 atomic mass units (amu)

- Hydrogen (H): 1.008 amu

- Oxygen (O): 16.00 amu

In CH3COOH, there are 2 carbon atoms, 4 hydrogen atoms, and 2 oxygen atoms.

So, the mass of one mole of acetic acid is:

(2 x 12.01 amu) + (4 x 1.008 amu) + (2 x 16.00 amu) = 60.052 amu

Therefore, one mole of acetic acid has a mass of approximately 60.052 atomic mass units.