The molecular weight of Octadecane (C₁₈H₃₈) is 254.4966.

Octadecane (C₁₈H₃₈) is an organic compound of two elements: Carbon, and Hydrogen. The molecular weight of Octadecane is 254.4966 which can be calculated by adding up the total weight (atomic weight multiplied by their number) of all its elements.

CALCULATION PROCEDURE: Octadecane  [C₁₈H₃₈] Molecular Weight Calculation

Step 1: Find the chemical formula and determine constituent atoms and their number in an Octadecane molecule.
You will know different atoms and their number in an Octadecane molecule from the chemical formula. The chemical formula of Octadecane is C₁₈H₃₈. The chemical formula shows that one Octadecane molecule consists of eighteen Carbon (C) atoms and thirty-eight Hydrogen (H) atoms.

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

Atomic weight of Carbon (C): 12.0107 (Ref: Jlab-ele006)
Atomic weight of Hydrogen (H): 1.008 (Ref: Lanl-1)

Step 3: Calculate the total weight of each atom in an Octadecane molecule by multiplying its atomic weight by its number.

Number of Carbon atoms in Octadecane: 18
Atomic weight of Carbon (C): 12.0107
Total weight of Carbon atoms in Octadecane: 12.0107 x 18 = 216.1926

Number of Hydrogen atoms in Octadecane: 38
Atomic weight of Hydrogen (H): 1.008
Total weight of Hydrogen atoms in Octadecane: 1.008 x 38 = 38.304

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

Molecular weight of Octadecane: 216.1926 (Carbon) + 38.304 (Hydrogen) = 254.4966

So the molecular weight of Octadecane is 254.4966.

Octadecane [C₁₈H₃₈] Molecular Weight Calculation

REFERENCES:

• Lanl-1: https://periodic.lanl.gov/1.shtml 
• Jlab-ele006: https://education.jlab.org/itselemental/ele006.html 

See also:

• Hydrogen chloride molecular weight calculation