How many molecules are present in a #0.05*cm^3# volume of LIQUID water under standard conditions?
We approach all these problems dimensionally. We want the answer as a dimensionless number, and our calculation should give us a dimensionless number if we do the correct product/quotient....
And number of moles
And so we take ....................
And we multiply this molar quantity by
And note that this approach gives us a dimensionless number as required.