Question

Please answer that question ​

Answer 1

1. mass = atomic mass of oxygen x number of moles

            = 16 x 0.5

             = 8 g

2. number of moles = no. of atoms / 6.023x10^23

                                = 3.011 x 10^23 / 6.023 x 10^23

                                 = 0.499

so, mass = atomic mass of oxygen x number of moles

                = 16 x 0.499

                 = 7.98 g

             (or)= 8 g (approx)