Calculate the mass of water that will be produced when 5.0 grams of H2 is reacted with excess O2.

To calculate the mass of water produced when 5.0 grams of H2 is reacted with excess O2, we need to use the balanced chemical equation for the reaction. The balanced equation for the reaction of H2 and O2 to form H2O is:

2 H2 + O2 → 2 H2O

From the equation, we can see that for every 2 moles of H2 reacted, 2 moles of H2O are produced.

To find the number of moles of H2, we divide the given mass by the molar mass of H2.

Molar mass of H2 = 2.016 g/mol

Number of moles of H2 = 5.0 g / 2.016 g/mol ≈ 2.48 mol

Since the reaction is balanced in a 1:1 ratio, the number of moles of H2O produced will be the same as the number of moles of H2.

Number of moles of H2O = 2.48 mol

To find the mass of H2O produced, we multiply the number of moles of H2O by its molar mass.

Molar mass of H2O = 18.015 g/mol

Mass of H2O produced = 2.48 mol * 18.015 g/mol ≈ 44.63 g

Therefore, the mass of water produced when 5.0 grams of H2 is reacted with excess O2 is approximately 44.63 grams.