To determine the mass of hydrogen (H) present in the compound, we need to consider the amount of hydrogen recovered from the combustion, which is 0.4909 g of water (H₂O).
Since water (H₂O) is composed of two hydrogen atoms, we can calculate the mass of hydrogen using the molar mass ratio between water and hydrogen.
The molar mass of water is 18.015 g/mol, and the molar mass of hydrogen is 1.008 g/mol.
Using the molar mass ratio:
(0.4909 g H₂O) * (2 mol H / 18.015 g H₂O) * (1.008 g/mol H) = 0.056 g H
Therefore, the mass of hydrogen present in the compound is approximately 0.056 g.