To determine the number of hydrogen atoms present in 36 grams of water (H2O), we need to consider the molar mass of water and the molar mass of hydrogen.
The molar mass of water (H2O) is calculated by summing the atomic masses of two hydrogen atoms (2 × 1.008 g/mol) and one oxygen atom (1 × 16.00 g/mol). Thus, the molar mass of water is:
Molar mass of H2O = (2 × 1.008 g/mol) + (1 × 16.00 g/mol) = 18.016 g/mol
Now, we can calculate the number of moles of water in 36 grams using the molar mass:
Number of moles = Mass / Molar mass = 36 g / 18.016 g/mol ≈ 1.998 mol
Since each water molecule (H2O) contains two hydrogen atoms, the number of moles of hydrogen atoms is double the number of moles of water:
Number of moles of hydrogen atoms = 2 × Number of moles of water = 2 × 1.998 mol ≈ 3.996 mol
Finally, to convert the number of moles of hydrogen atoms to the number of hydrogen atoms, we multiply by Avogadro's number, which is approximately 6.022 × 10^23 atoms/mol:
Number of hydrogen atoms = Number of moles × Avogadro's number = 3.996 mol × 6.022 × 10^23 atoms/mol ≈ 2.406 × 10^24 hydrogen atoms
Therefore, approximately 2.406 × 10^24 hydrogen atoms are present in 36 grams of water.