Question

Calculate the mass in grams of 6.71 x 10^25 molecules of water

Answer 1

1 mole of water would have $6.02 ×10^{23}$ (avogadro's constant)

Molar mass of water = 1(2)+16 = 18

Hence

$6.71×10^{25}$ molecules of water would have a mass of:

$(\frac{18}{6.02×10^{23}} ) 6.71 ×10^{25} = 2006.3 g$