Molecular Formula Calculator

Calculate molecular weight and elemental composition of chemical compounds. Supports complex formulas with parentheses and hydrates.

CuSO₄·5H₂O
Enter chemical formula using standard notation. Use parentheses for groups and dots for hydrates.
H₂O
C₆H₁₂O₆
NaCl
CH₃COOH
CaCO₃
C₂H₅OH
Complex Formulas
Ca(OH)₂
Al₂(SO₄)₃
CuSO₄·5H₂O
Fe(NO₃)₃·9H₂O
(NH₄)₂SO₄
Calculating...
Molecular Formula Results

Understanding Molecular Formulas

A molecular formula represents the number and type of atoms present in a molecule of a chemical compound. It provides information about the composition of the compound but not its structure.

Key Insight: The molecular weight (or molecular mass) is the sum of the atomic weights of all atoms in a molecule. It's typically expressed in grams per mole (g/mol).

Types of Chemical Formulas

1

Molecular Formula: Shows the actual number of atoms of each element in a molecule (e.g., C₆H₁₂O₆ for glucose).

2

Empirical Formula: Shows the simplest whole-number ratio of atoms in a compound (e.g., CH₂O for glucose).

3

Structural Formula: Shows how atoms are connected in the molecule, providing information about molecular structure.

4

Condensed Formula: A simplified structural formula that groups atoms together (e.g., CH₃CH₂OH for ethanol).

How to Write Chemical Formulas

  • Element Symbols: Use standard chemical symbols (H for hydrogen, O for oxygen, etc.)
  • Subscripts: Use subscripts to indicate the number of atoms (H₂O has 2 hydrogen atoms and 1 oxygen atom)
  • Parentheses: Use parentheses for groups of atoms (e.g., Ca(OH)₂ has one calcium, two oxygen, and two hydrogen atoms)
  • Hydrates: Use a dot (·) to separate water molecules in hydrates (e.g., CuSO₄·5H₂O)
  • Order of Elements: For organic compounds, carbon is listed first, then hydrogen, followed by other elements in alphabetical order
  • Charges: For ions, indicate the charge with a superscript (e.g., SO₄²⁻ for sulfate ion)

Common Chemical Compounds

Compound Formula Molecular Weight (g/mol) Common Name
Water H₂O 18.015 -
Table Salt NaCl 58.44 Sodium chloride
Calcium Hydroxide Ca(OH)₂ 74.09 Slaked lime
Copper Sulfate Pentahydrate CuSO₄·5H₂O 249.69 Blue vitriol
Ammonium Sulfate (NH₄)₂SO₄ 132.14 -
Aluminum Sulfate Al₂(SO₄)₃ 342.15 Alum

Applications of Molecular Weight Calculation

Molecular weight calculations are essential in various fields:

  • Chemistry: Determining reaction stoichiometry and preparing solutions
  • Pharmaceuticals: Calculating drug dosages and formulation concentrations
  • Biochemistry: Studying proteins, nucleic acids, and other biomolecules
  • Materials Science: Characterizing polymers and other materials
  • Environmental Science: Analyzing pollutants and their behavior

Note: This calculator uses standard atomic weights based on the IUPAC 2021 values. For precise scientific work, always use the most current atomic weight values from authoritative sources.

Frequently Asked Questions

The calculator uses standard atomic weights based on IUPAC recommendations. For most common elements, these values are highly accurate. However, some elements have natural isotopic variations that can slightly affect the molecular weight in real-world samples.

Yes, the calculator can handle formulas with parentheses, such as Ca(OH)₂ or Al₂(SO₄)₃. The algorithm correctly interprets the subscript outside the parentheses as applying to all elements within the parentheses.

The calculator recognizes the dot (·) as a separator for hydrate formulas. For example, CuSO₄·5H₂O is treated as CuSO₄ and 5H₂O combined. The calculator will parse both parts separately and then combine the element counts to calculate the total molecular weight.

If you encounter an "Unknown element" error, it means the element symbol is not recognized. Check for typos in the element symbol. The calculator includes all standard elements from hydrogen to uranium. If you need to calculate with an element not in our database, please contact us to request its addition.

The calculator can handle nested parentheses, such as in complex coordination compounds. The algorithm uses a stack-based approach to correctly parse nested structures and apply multipliers to all elements within each set of parentheses.