Calculadora De Peso Molecular
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Reviewed by Calculator Editorial Team
The molecular weight calculator helps determine the molecular weight of chemical compounds by summing the atomic weights of all atoms in the molecule. This is essential for stoichiometry, chemical reactions, and understanding molecular properties.
What is Molecular Weight?
Molecular weight, also known as molecular mass, is the sum of the atomic weights of all atoms in a molecule. It's expressed in atomic mass units (u) and is crucial for:
- Balancing chemical equations
- Determining reaction stoichiometry
- Calculating molar concentrations
- Understanding molecular properties
The molecular weight differs from molar mass in that it's calculated based on the molecular formula, while molar mass includes the mass of solvent in solution.
How to Use the Calculator
To calculate the molecular weight:
- Enter the chemical formula in the input field
- Click "Calculate" to get the result
- Review the detailed breakdown of atomic contributions
The calculator uses standard atomic weights from the IUPAC periodic table.
Formula
Molecular Weight Formula
Molecular Weight = Σ (Atomic Weight × Number of Atoms)
Where Σ represents the sum of all atoms in the molecule.
The formula accounts for all atoms in the molecular structure, including hydrogen, carbon, oxygen, and other elements.
Example Calculation
Example: Water (H₂O)
Atomic weights:
- Hydrogen (H): 1.008 u
- Oxygen (O): 15.999 u
Calculation:
(2 × 1.008) + 15.999 = 2.016 + 15.999 = 18.015 u
Result: The molecular weight of water is 18.015 u.
FAQ
What is the difference between molecular weight and molar mass?
Molecular weight refers to the mass of a single molecule, while molar mass includes the mass of solvent in a solution. For pure compounds, they are essentially the same.
How accurate is the calculator?
The calculator uses standard atomic weights from the IUPAC periodic table, providing accurate results for most common compounds.
Can I calculate the molecular weight of polymers?
Yes, but you'll need to know the exact molecular formula or repeat unit structure of the polymer.
What units are used for molecular weight?
Molecular weight is expressed in atomic mass units (u), where 1 u is approximately the mass of a single proton or neutron.