find the mass?

Question

3.01 X 10^23 molecules H2S

Answer 1

6.02 10^23 is the number of molecules in a mole.

Here 3.01 10^23 is half that quantity.

So you have a mass of H2S divided by two

mass of H2S = 32+2 =34

you have 34/2 = 17g of H2S

Answer 2

1 gm of any compound / element at STP contains 6.023 x 10^23 molecules.(Avogadro's No.)
Therefore mass of 6.023 x 10^23 molecules of H2S is 34. (atomic wt of H = 1, S = 32)
So 3.01 x 10^23 molecules of H2S will have a mass = apx half of 34 ; So the answer is 17.