Answer:
3.01 x 10²¹
Explanation:
Molar mass of h₂o =18.01528 g/mol.
it means 1 mole h₂o=18.01528 g .....(1)
1 mole = 6.022 × 10^23 molecules
so,
1 mole h₂o =6.022 × 10^23 molecules=18.01528 g [from 01]
now,
18.01528 g h₂o has= 6.022 × 10^23 molecules
9.00x10⁻² g h₂o has= ( 6.022 × 10^23 x 9.00x10⁻² ) /18.01528 molecules
=3.008 x 10²¹ molecules
≈ 3.01 x 10²¹ molecules
