how many h2 can be produced by 9.2 gr with h2o

Answer 1

a mol of H2O has mass of 2+16 = 18 grams
so we have 9.2/18 = .511 mols of H2O

that is .511 mols of H2

.511 * 6.02*10^23 = 3.08*10^23 molecules of H2

Answer 2

moles of H2O in 9.2 grams: moles=9.2/18=you do it.

Moles of H2 in one mole of H2O: one

so you get 9.2/18 moles of H2.
That is 9.2/18 * 2 grams.