How To Find The Mass Of One Molecule?

Find the molar mass of the compound:

The molar mass is the mass of one mole of a substance (usually given in grams per mole, g/mol). It is found by adding the atomic masses of all the atoms in the molecule.

Example:

• For water (H₂O), the atomic masses are:
  • Hydrogen (H): 1.008 g/mol
  • Oxygen (O): 16.00 g/mol
• Molar mass of H₂O = (2 × 1.008) + (1 × 16.00) = 18.016 g/mol

Convert the molar mass to the mass of a single molecule:

To find the mass of one molecule, divide the molar mass by Avogadro’s number (6.022 × 10²³ molecules per mole), which gives the number of molecules in one mole.

Formula:

    Mass of one molecule=Avogadro’s number (mol−1)Molar mass (g/mol)​

 Example Calculation:

For water (H₂O), the molar mass is 18.016 g/mol. To find the mass of one molecule:

Mass of one H₂O molecule=6.022×1023mol−118.016g/mol​≈3.00×10−23grams

So, the mass of one water molecule is approximately 3.00 × 10⁻²³ grams.

Summary:

•  Find the molar mass of the compound.
•  Divide the molar mass by Avogadro’s number (6.022 × 10²³).
• The result gives the mass of one molecule in grams.