To determine which sample has the greatest mass of hydrogen, we'll examine the molecular composition and molar masses of each compound.
1. Molar Mass Calculations:
- For [tex]\(H_2O\)[/tex]:
- Hydrogen (H) has a molar mass of approximately 1.008 g/mol.
- Oxygen (O) has a molar mass of approximately 16.00 g/mol.
- Molar mass of [tex]\(H_2O\)[/tex] = 2 1.008 g/mol (for H atoms) + 16.00 g/mol (for O atom)
= 2.016 g/mol + 16.00 g/mol
= 18.016 g/mol.
- For [tex]\(H_2S\)[/tex]:
- Sulfur (S) has a molar mass of approximately 32.06 g/mol.
- Molar mass of [tex]\(H_2S\)[/tex] = 2 1.008 g/mol (for H atoms) + 32.06 g/mol (for S atom)
= 2.016 g/mol + 32.06 g/mol
= 34.076 g/mol.
- For [tex]\(H_2Se\)[/tex]:
- Selenium (Se) has a molar mass of approximately 78.96 g/mol.
- Molar mass of [tex]\(H_2Se\)[/tex] = 2 1.008 g/mol (for H atoms) + 78.96 g/mol (for Se atom)
= 2.016 g/mol + 78.96 g/mol
= 80.976 g/mol.
2. Mass of Hydrogen in Each Molecule:
To find the mass of hydrogen in each molecule, we calculate the fraction of the molar mass that is due to hydrogen.
- For [tex]\(H_2O\)[/tex]:
- Mass of hydrogen = (2 1.008 g/mol) / 18.016 g/mol
≈ 0.112 \\\\\\\\\\\\\\\\\\\\\\
- For [tex]\(H_2S\)[/tex]:
- Mass of hydrogen = (2 1.008 g/mol) / 34.076 g/mol
≈ 0.059 \\\\\\\\\\\
- For [tex]\(H_2Se\)[/tex]:
- Mass of hydrogen = (2 1.008 g/mol) / 80.976 g/mol
≈ 0.025 \\\\\\2
3. Comparison:
Comparing these values:
- Approximately 0.112 for [tex]\(H_2O\)[/tex]
- Approximately 0.059 for [tex]\(H_2S\)[/tex]
- Approximately 0.025 for [tex]\(H_2Se\)[/tex]
The greatest fraction of the total mass that comes from hydrogen is in [tex]\(H_2O\)[/tex].
Therefore, the sample with the greatest mass of hydrogen is a mole of [tex]\(H_2O\)[/tex].
Correct Answer:
A mole of [tex]\(H_2O\)[/tex]
