Molecular Weight Calculator

Alfa Chemistry offers a Molecular Weight Calculator for calculating the average molecular weight (MW) of compounds. By entering a chemical formula or selecting from a predefined list of common organic compounds and elements, users can quickly determine the molecular weight of a substance. The calculator is essential for applications in stoichiometry, chemical synthesis, and analytical chemistry.

Molecular Weight Calculator

Common Organic Compounds:

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Elements of the periodic table:

-- Select an element --

Chemical formula:

Calculate

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Total Molecular Weight:

How to use the calculator

• Enter the chemical formula: Enter the molecular formula of the compound, making sure the symbols are correct (e.g., H2SO4 for sulfuric acid). Click “Calculate”: the tool processes the molecular formula and displays the molecular weight.
• Use the predefined list: Select a compound from the built-in list of common organic molecules or individual elements.

Note:

• The calculator can handle up to two different levels of parentheses.
• Be sure to enter the correct crystalline molecule, e.g. CH3COONa-3H2O.
• Make sure the element symbols and capitalization are correct (e.g., CO for carbon monoxide, Co for cobalt).
• The tool does not take into account isotopic variations unless otherwise stated.

What Is Molecular Weight?

Molecular weight (MW), also known as molecular mass, is the sum of the atomic weights of all atoms in a given molecule. It is typically expressed in atomic mass units (amu) or Daltons (Da). Molecular weight plays a crucial role in various scientific disciplines, including chemistry, biochemistry, and materials science.

Calculation Formula of Molecular Weight

The molecular weight (MW) of a compound is determined using the formula:

MW = N₁ × MW₁＋N₂ × MW₂＋…＋N_n × MW_n

Where:

• N_n = Number of atoms of element n in the molecule
• MW_n = Atomic mass of element n (referencing the periodic table)

For example, the molecular weight of water (H₂O) is calculated as: 2 × 1.008＋1 × 16.00 = 18.016 g/mol

Applications

• Stoichiometry: Balancing chemical reactions and determining reactant-product mass relationships.
• Solution Preparation: Calculating molar concentrations for laboratory reagents.
• Material Science: Analyzing polymer structures and molecular compositions.
• Environmental Chemistry: Estimating pollutant dispersion and molecular impact.

Please kindly note that our products are for research use only.