The molecular weight of Acetaldehyde (CH₃CHO) is 44.0528.

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: Acetaldehyde (CH₃CHO) Molecular Weight Calculation

Step 1: Find out the chemical formula and determine constituent atoms and their number in a Acetaldehyde molecule.
From the chemical formula, you will know different atoms and their number in a Acetaldehyde molecule. Chemical formula of Acetaldehyde is C₂H₄O. From the chemical formula of Acetaldehyde, you can find that one molecule of Acetaldehyde has two Carbon (C) atoms, 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 Acetaldehyde molecule by multiplying its atomic weight by its number.

Number of Carbon atoms in Acetaldehyde: 2
Atomic weight of Carbon: 12.0107
Total weight of Carbon atoms in Acetaldehyde: 12.0107 x 2 = 24.0214

Number of Hydrogen atoms in Acetaldehyde: 4
Atomic weight of Hydrogen: 1.008
Total weight of Hydrogen atoms in Acetaldehyde: 1.008 x 4 = 4.032

Number of Oxygen atoms in Acetaldehyde: 1
Atomic weight of Oxygen: 15.9994
Total weight of Oxygen atoms in Acetaldehyde: 15.9994 x 1 = 15.9994

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

Molecular weight of Acetaldehyde: 24.0214 (Carbon) + 4.032 (Hydrogen) + 15.9994 (Oxygen) = 44.0528

So the molecular weight of Acetaldehyde is 44.0528.

Acetaldehyde (CH₃CHO) 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