The molecular weight of Allolactose (C₁₂H₂₂O₁₁) is 342.2978.

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: Allolactose (C₁₂H₂₂O₁₁) Molecular Weight Calculation

Step 1: Find out the chemical formula and determine constituent atoms and their number in a Allolactose molecule.
From the chemical formula, you will know different atoms and their number in a Allolactose molecule. Chemical formula of Allolactose is C₁₂H₂₂O₁₁. From the chemical formula of Allolactose, you can find that one molecule of Allolactose have twelve Carbon (C) atoms, twenty two Hydrogen (H) atoms and eleven 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 Allolactose molecule by multiplying its atomic weight by its number.

Number of Carbon atoms in Allolactose: 12
Atomic weight of Carbon: 12.0107
Total weight of Carbon atoms in Allolactose: 12.0107 x 12 = 144.1284

Number of Hydrogen atoms in Allolactose: 22
Atomic weight of Hydrogen: 1.008
Total weight of Hydrogen atoms in Allolactose: 1.008 x 22 = 22.176

Number of Oxygen atoms in Allolactose: 11
Atomic weight of Oxygen: 15.9994
Total weight of Oxygen atoms in Allolactose: 15.9994 x 11 = 175.9934

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

Molecular weight of Allolactose: 144.1284 (Carbon) + 22.176 (Hydrogen) + 175.9934 (Oxygen) = 342.2978

So the molecular weight of Allolactose is 342.2978.

Allolactose (C₅H₁₀O₅) 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