Molecular Weight Calculator

    Enter a chemical formula like H2O, Ca(OH)2, or CuSO4·5H2O to calculate its molecular weight.

    Formula

    Supports parentheses ( ), brackets [ ], braces {}, and hydrates (·)

    Example Formulas

    About Molecular Weight

    Molecular weight, also known as molar mass, is the sum of the atomic weights of all atoms in a molecule. It is a fundamental property used in chemistry to relate the mass of a substance to the amount in moles. Accurate molecular weight calculations are essential for stoichiometry, solution preparation, and chemical reactions. Special attention is required for compounds with parentheses, hydrates, or multiple polyatomic groups, which must be expanded correctly to calculate the total molar mass.

    •Supported Features

    • –Simple formulas: H2O, CO2, NaCl, C6H12O6
    • –Parentheses: Ca(OH)2, Al2(SO4)3, Mg(NO3)2
    • –Brackets and braces: [Cu(NH3)4]SO4, Fe4[Fe(CN)6]3
    • –Hydrates with dot notation: CuSO4·5H2O, Na2CO3·10H2O
    • –Comprehensive element database: 92 elements from H to U
    • –Element breakdown with contributions and percentages

    •Features

    • –Calculates molecular weight for any chemical formula, including organic and inorganic compounds.
    • –Handles hydrates, parentheses, brackets, and polyatomic ions accurately using stack-based parsing.
    • –Supports elements with fractional atomic weights based on the latest IUPAC standards.
    • –Provides detailed breakdown of atom counts and contributions to total molecular weight.
    • –Ideal for chemistry students, lab calculations, and chemical engineering applications.

    •How to Use

    1. 1.Enter the chemical formula of the compound (e.g., H2O, Ca(OH)2, CuSO4·5H2O).
    2. 2.The calculator will parse the formula, counting each atom and group correctly.
    3. 3.Click "Calculate" to determine the total molecular weight in g/mol.
    4. 4.Review the breakdown to see contributions from each element or polyatomic group.
    5. 5.Use the molecular weight for stoichiometry, solution preparation, and reaction calculations.

    •Key Concepts

    • –Molecular Weight (Molar Mass): Sum of atomic weights in g/mol.
    • –Atomic Weight: Average mass of an element's atoms based on isotopic composition.
    • –Hydrates: Include water molecules in the formula (e.g., CuSO4·5H2O).
    • –Parentheses: Multiply the atoms inside by the number outside (e.g., Ca(OH)2).
    • –Polyatomic Groups: Treat as a single unit when inside parentheses.

    •Formula Used

    • –Molecular Weight: M = Σ (Atomic Weight × Number of Atoms)
    • –Example: H2O → (2 × 1.008) + (1 × 15.999) = 18.015 g/mol
    • –With Hydrate: CuSO4·5H2O → 159.609 + (5 × 18.015) = 249.684 g/mol

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