50g H2O(2.016g H/18.02g H2O) = 5.59g H

50.0g H2O * (2.016g H / 18.02g H2O) = 5.59g H

1 mole of water would be 16 + 2 = 18g

50g of water = 50/18 = 2.77 moles

2.77 moles of hydrogen would be 2.77 x 2 = 5.56 g of hydrogen.

H2O is 2 grammes of Hydrogen to 16 grammes of Oxygen

so we get 50 x (2/18) you o the math