What would be the mass of 1.98x10^28 molecules of water

The mass of water would be

Explanation:

According to the mole concept:

1 mole of a compound contains number of molecules which determines the molar mass of that compound.

Mass of water for 1 mole is 18 grams.

So, number of molecules will have a mass of

Hence, the mass of water would be

"the periodic table is arranged in order of atomic number."