Question

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

Answer 1

Step-by-step explanation:

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

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

=3.011*10^21

Answer 2

3.01 x 10²¹

Step-by-step 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