Question

Pls help! I’m not very smart so please explain it to me!

Answer 1

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

Answer 2

Answer:

Explanation:

no. of molecules = mass/ molar mass *6.022*10 ^23

                         =9.00*10^-2/18*6.022*10^23

                        =3.011*10^21