Question

What is the mass of one mole of water?

Answer 1

According to the mole concept, the mass of one mole is nothing but the molar mass of that compound (atomic mass when we are talking about atoms).
The general process of calculating the molar mass of any compound is completely applicable here.

Complete step-by-step answer: Let us study about the concept of molar mass in detail;
Molar mass-
It is the mass of one mole of any substance present in its actual state. It is calculated as the sum of the standard atomic masses of the comprising atoms.
To calculate the mass of one mole of water or molar mass of water, the steps are;
Symbol of water $\Rightarrow {{H}_{2}}O$
Atomic mass of H = 1 gm
Atomic mass of O = 16 gm
Thus, the molar mass of ${{H}_{2}}O=\left( 2\times 1 \right)+16=18gm/mol$

Note: Do note that the unit of molar mass is gm/mole thus, when we calculate the mass of one mole of water it is simply equal to the molar mass units i.e. 18 gm/mole.
More precisely, often the average molar mass is calculated to avoid confusion, so we can say that the mass of one mole of water is 18.02 amu.