The molecular weight of Formic Acid (HCOOH) is 46.0255.

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: Formic Acid (HCOOH) Molecular Weight Calculation

Step 1: Find out the chemical formula and determine constituent atoms and their number in a Formic Acid molecule.
From the chemical formula, you will know different atoms and their number in a Formic Acid molecule. Chemical formula of Formic Acid is CH₂O₂. From the chemical formula of Formic Acid, you can find that one molecule of Formic Acid has one Carbon (C) atom, two Hydrogen (H) atoms and two Oxygen (O) atoms.

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 Formic Acid molecule by multiplying its atomic weight by its number.

Number of Carbon atoms in Formic Acid: 1
Atomic weight of Carbon: 12.0107
Total weight of Carbon atoms in Formic Acid: 12.0107 x 1 = 12.0107

Number of Hydrogen atoms in Formic Acid: 2
Atomic weight of Hydrogen: 1.008
Total weight of Hydrogen atoms in Formic Acid: 1.008 x 2 = 2.016

Number of Oxygen atoms in Formic Acid: 2
Atomic weight of Oxygen: 15.9994
Total weight of Oxygen atoms in Formic Acid: 15.9994 x 2 = 31.9988

Step 4: Calculate the molecular weight of Formic Acid by adding up the total weight of all atoms.

Molecular weight of Formic Acid: 12.0107 (Carbon) + 2.016 (Hydrogen) + 31.9988 (Oxygen) = 46.0255

So the molecular weight of Formic Acid is 46.0255.

Formic Acid (HCOOH) Molecular Weight Calculation

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

See also:

• Apiose (C5H10O5) Molecular Weight Calculation