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Molecular Weight Calculation:
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Molecular weight (MW) is the sum of the atomic weights of all atoms in a molecule. It's expressed in grams per mole (g/mol) and is fundamental in chemistry for stoichiometric calculations and determining molecular properties.
The calculator uses the formula:
Where:
Explanation: The calculator parses the molecular formula, identifies each element and its count, then sums the products of atom counts and their respective atomic weights.
Details: Molecular weight is crucial for preparing solutions with specific concentrations, calculating reaction yields, determining empirical and molecular formulas, and in various analytical techniques like mass spectrometry.
Tips: Enter the molecular formula using standard chemical notation (e.g., H2O, C6H12O6, NaCl). Element symbols are case-sensitive (first letter uppercase, second lowercase if applicable).
Q1: What's the difference between molecular weight and molar mass?
A: They are numerically identical but molecular weight refers to molecules while molar mass is a more general term that can apply to compounds, elements, or ions.
Q2: How accurate are the atomic weights used?
A: We use standard atomic weights based on IUPAC recommendations, which represent typical terrestrial abundances of elements.
Q3: Can this calculator handle complex formulas with parentheses?
A: The current version handles simple formulas without nested parentheses. For complex formulas, consider breaking them down into simpler components.
Q4: Does it work for ions and charged molecules?
A: The calculator computes molecular weight based on the formula entered. For ions, it will calculate the mass of the formula as entered without accounting for charge.
Q5: What about isotopes and isotopic distributions?
A: This calculator uses average atomic weights. For precise isotopic calculations, specialized mass spectrometry software would be needed.