M (H2O)

It seems like you're asking about the molar mass of water (H₂O).

The molar mass of water is calculated by adding the molar masses of its constituent elements:

• Hydrogen (H): approximately 1.01 g/mol
• Oxygen (O): approximately 16.00 g/mol

Since there are two hydrogen atoms and one oxygen atom in a water molecule, the calculation would be:

\[ \text{Molar mass of H₂O} = (2 \times 1.01 \, \text{g/mol}) + (1 \times 16.00 \, \text{g/mol}) \] \[ = 2.02 \, \text{g/mol} + 16.00 \, \text{g/mol} \] \[ = 18.02 \, \text{g/mol} \]

Therefore, the molar mass of water (H₂O) is approximately 18.02 g/mol. If you have a specific context or further questions regarding H₂O, feel free to ask!