ANSWER

The molecular weight of acetic acid (CH3COOH) is 60.052.

CALCULATION PROCEDURE

Step 1: Find out the chemical formula of acetic acid. 
With the chemical formula, you will know different atoms and their number in an acetic acid molecule. Chemical formula of acetic acid is CH3COOH. From the chemical formula/structure of acetic acid, it is easy to find out that there are two Carbon (C) atoms, four hydrogen (H) atoms and two oxygen (O) atoms in a molecule of acetic acid. 

Step 2: Find out atomic weights of each atom (from periodic table). 

Atomic weight of Carbon (C) : 12.011

Atomic weight of hydrogen (H): 1.008

Atomic weight of oxygen (O): 15.999

Step 3: Calculate the total weight of each atom present in acetic acid. 

Formula:

Total weight of a atom in acetic acid: Atom’s atomic weight x total number of atoms in acetic acid

Number of carbon atoms in acetic acid: 2
Atomic weight of carbon (C) : 12.011
Total weight of carbon atoms in acetic acid: 24.022

Number of hydrogen atoms in acetic acid: 4
Atomic weight of hydrogen: 1.008
Total weight of hydrogen atoms in acetic acid: 4.032

Number of oxygen atoms in acetic acid: 2
Atomic weight of oxygen: 15.999
Total weight of oxygen atoms in acetic acid: 31.998

Step 4: Calculate the molecular weight of acetic acid by adding total atomic weight of all atoms. 

Molecular weight of acetic acid (CH3COOH): 

24.022 (12.011 x 2 carbon) + 4.032 (1.008 x 4 hydrogen) + 31.998 (15.999 x 2 oxygen)

So the molecular weight of acetic acid is 60.052.