Anonymous

Water molecule (H₂O) H₂ - 2.5 gm O - ? H₂ is 2g / mol O is 16g / mol ∵ (16 is mass of oxygen) 2g Hydrogen react with 16 g of oxygen ∴ 2.5 g / 2.0 g x 16g = 20.0 g.

Anonymous

Water is H2O H has molar mass 1g/mol H2 is 2g/mol and O is 16g/mol 2g hydrogen reacts with 16g O 2.5g H2 will react with 2.5g/2.0g * 16g = 20.0g

Anonymous

use a proportion 2 g H combines with 16 g O [ to form 18 g water <<< last part is not needed] 2gH / 16gO = 2,5gH / x g O <<< solve for x x = 16*2.5/2 = 20 g Oxygen

Anonymous

2H2 + O2 = 2H2O molar ratios are 2:1::2 moles(H2) = 2.5 / 2 = 1.25 moles Hence by equivalence of molar ratios moles(H2O) formed is 1.25 moles moles(O2) reuired is 1.25 / 2 = 0.625 moles Mass O2) = 32 x 0.625 = 20 g.