1) HCL 2)H2S 3)HNO3 4) H2SO4 5)H2O contains the lowest percent by mass of hydrogen.
mass of hydrogen/mass of compound
times 100 to get %
To determine which compound contains the lowest percent by mass of hydrogen, we need to calculate the percent composition of hydrogen in each compound.
The percent composition of an element in a compound is calculated by dividing the mass of the element by the molar mass of the compound and multiplying by 100.
Let's calculate the percent composition of hydrogen in each compound:
1) HCL (hydrochloric acid):
- Molar mass of HCL = 1.01 g/mol (hydrogen) + 35.45 g/mol (chlorine) = 36.46 g/mol
- Mass of hydrogen in HCL = 1.01 g/mol
- Percent composition of hydrogen in HCL = (1.01 g/mol / 36.46 g/mol) × 100% ≈ 2.77%
2) H2S (hydrogen sulfide):
- Molar mass of H2S = 2.02 g/mol (hydrogen) + 32.07 g/mol (sulfur) = 34.09 g/mol
- Mass of hydrogen in H2S = 2.02 g/mol × 2 = 4.04 g/mol
- Percent composition of hydrogen in H2S = (4.04 g/mol / 34.09 g/mol) × 100% ≈ 11.87%
3) HNO3 (nitric acid):
- Molar mass of HNO3 = 1.01 g/mol (hydrogen) + 14.01 g/mol (nitrogen) + (3 × 16.00 g/mol) (oxygen) = 63.01 g/mol
- Mass of hydrogen in HNO3 = 1.01 g/mol
- Percent composition of hydrogen in HNO3 = (1.01 g/mol / 63.01 g/mol) × 100% ≈ 1.61%
4) H2SO4 (sulfuric acid):
- Molar mass of H2SO4 = 2.02 g/mol (hydrogen) + 32.07 g/mol (sulfur) + (4 × 16.00 g/mol) (oxygen) = 98.09 g/mol
- Mass of hydrogen in H2SO4 = 2.02 g/mol × 2 = 4.04 g/mol
- Percent composition of hydrogen in H2SO4 = (4.04 g/mol / 98.09 g/mol) × 100% ≈ 4.12%
5) H2O (water):
- Molar mass of H2O = 2.02 g/mol (hydrogen) + 16.00 g/mol (oxygen) = 18.02 g/mol
- Mass of hydrogen in H2O = 2.02 g/mol × 2 = 4.04 g/mol
- Percent composition of hydrogen in H2O = (4.04 g/mol / 18.02 g/mol) × 100% ≈ 22.45%
Therefore, among the given compounds, HCL has the lowest percent by mass of hydrogen (approximately 2.77%).