The balanced chemical equation for the reaction between hydrogen gas (H2) and oxygen gas (O2) to form water (H2O) is:
2 H2 + O2 → 2 H2O
According to the stoichiometry of this equation, it shows that 2 moles of H2 react with 1 mole of O2 to produce 2 moles of H2O.
Given that you have 8 grams of H2, we can calculate the number of moles of H2 by using its molar mass, which is approximately 2 grams/mole.
Number of moles of H2 = Mass of H2 / Molar mass of H2 = 8 grams / 2 grams/mole = 4 moles
From the balanced equation, we know that 2 moles of H2 react to produce 2 moles of H2O. Therefore, the number of moles of water formed will be equal to the number of moles of hydrogen gas:
Number of moles of water = Number of moles of H2 = 4 moles
So, when 8 grams of H2 react with 2 moles of oxygen, 4 moles of water will be formed.