Question

calculate number of moles present in 3.011 × 10²²atom of H2O

Answer 1

1mole equal to 6.23*10²³ atom

lets there are n mole so

n*6.022*10²³=3.011*10²²
n=3.011*10²²/6.022*10²³
=1/20
0.05 moles

Answer 2

Molar mass of H20 = 18g 

And in 18 g there is 1 mole = 6.022 x 10 ²³ atoms 

1mole = 6.022 x 10²³ 

1/6.022 x 10 ²³ = 1 atom 

1x 3.011 x 10²²/ 6.022 x 10²³ = 3.011 x 10²² atoms 

1/20 = 3.011 x 10²² atoms 

0.05 moles = 3.011 x 10²²atoms