Which scientific tool is most useful when trying to convert a known amount of grams of water to moles of water?

The periodic table

Explanation:

The periodic table can show the atomic number and atomic mass of any atoms easily. To convert grams of water to moles of water, you need to know the atoms that made up water molecules then find out their molecular mass. Water is made of two hydrogens and one oxygen atoms. Then you can find the atomic mass of hydrogens is 1 while oxygen is 16. The molecular mass of water will be 2*1 + 16= 18g/mol.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.