The molecular weight of Methanol (CH3OH) is 32.0421.
To calculate molecular weight of any compound, the first step is to know the constituent atoms and their number in that particular compound. Then calculate the total weight of each atom by multiplying its atomic weight by its number. The sum of total weight of all constituent atoms will be the molecular weight of the compound. Note that the value of atomic weight may differ slightly from different sources.
CALCULATION PROCEDURE: Methanol (CH3OH) Molecular Weight Calculation
Step 1: Find out the chemical formula and determine constituent atoms and their number in a Methanol molecule.
From the chemical formula, you will know different atoms and their number in a Methanol molecule. Chemical formula of Methanol is CH4O. From the chemical formula of Methanol, you can find that one molecule of Methanol has one Carbon (C) atom, four Hydrogen (H) atoms and one Oxygen (O) atom.
Step 2: Find out atomic weights of each atom (from periodic table).
Atomic weight of Carbon (C): 12.0107 (Ref: Jlab-ele006)
Atomic weight of Hydrogen (H) : 1.008 (Ref: Lanl-1)
Atomic weight of Oxygen (O) : 15.9994 (Ref: Jlab-ele008)
Step 3: Calculate the total weight of each atom present in a Methanol molecule by multiplying its atomic weight by its number.
Number of Carbon atoms in Methanol: 1
Atomic weight of Carbon: 12.0107
Total weight of Carbon atoms in Methanol: 12.0107 x 1 = 12.0107
Number of Hydrogen atoms in Methanol: 4
Atomic weight of Hydrogen: 1.008
Total weight of Hydrogen atoms in Methanol: 1.008 x 4 = 4.032
Number of Oxygen atoms in Methanol: 1
Atomic weight of Oxygen: 15.9994
Total weight of Oxygen atoms in Methanol: 15.9994 x 1 = 15.9994
Step 4: Calculate the molecular weight of Methanol by adding up the total weight of all atoms.
Molecular weight of Methanol: 12.0107 (Carbon) + 4.032 (Hydrogen) + 15.9994 (Oxygen) = 32.0421
So the molecular weight of Methanol is 32.0421.
Methanol (CH3OH) Molecular Weight Calculation
| Molecular weight of Methanol | |||
| Constituent atoms | Number of each atom | Atomic weight | Total weight |
| Carbon (C) | 1 | 12.0107 | 12.0107 |
| Hydrogen (H) | 4 | 1.008 | 4.032 |
| Oxygen (O) | 1 | 15.9994 | 15.9994 |
| Molecular weight of Methanol: | 32.0421 | ||
REFERENCES:
- Lanl-1: https://periodic.lanl.gov/1.shtml
- Pubchem-Hydrogen : https://pubchem.ncbi.nlm.nih.gov/element/Hydrogen
- Jlab-ele006; https://education.jlab.org/itselemental/ele006.html
- Pubchem-6: https://pubchem.ncbi.nlm.nih.gov/element/6
- Jlab-ele008: https://education.jlab.org/itselemental/ele008.html
- Pubchem-8: https://pubchem.ncbi.nlm.nih.gov/element/8
