Answer :
Step 1 - Calculating and interpreting the molar mass of water
The molar mass of water can be obtained from the molar masses of its constituent elements: H and O. These, in turn, can be found at a periodic table: 1 g/mol for H and 16 g/mol for O.
Since water's molecular formula is H2O, its molar mass will be:
[tex]M_{H2O}=2\times1+16=18g/mol[/tex]This means that, in 18g of water, there is one mole of water molecules. One mole, in turn, corresponds to 6.02*10^23 molecules.
Step 2 - Calculating the mass in grams of a single water molecule
Now that we know the mass of 6.02*10^23 water molecules, we can use it to calculate the mass of a single water molecule:
[tex]\begin{gathered} 6.02\times10^{23}\text{ H2O molecules weights ---- 18g} \\ 1\text{ H2O molecule would weight ------ - x} \\ \\ x=\frac{18}{6.02}\times10^{-23}=2.9\times10^{-23}g \end{gathered}[/tex]The mass in grams of a single water molecule is therefore ~3*10(-23) grams.
