Arrange the following compounds in order from smallest to largest molar mass: H2O, CO2, NH3, CH4.

• A. NH3, CH4, H2O, CO2
• B. CO2, H2O, NH3, CH4
• C. H2O, CH4, NH3, CO2
• D. CH4, NH3, H2O, CO2

Answer: (D)

Verified step by step guidance

1. Identify the molecular formula of each compound: H\_2O (water), CO\_2 (carbon dioxide), NH\_3 (ammonia), and CH\_4 (methane).
2. Calculate the molar mass of each compound by summing the atomic masses of all atoms in the molecule. Use approximate atomic masses: H = 1 g/mol, C = 12 g/mol, O = 16 g/mol, N = 14 g/mol.
3. For CH\_4, calculate molar mass as: 1 carbon atom (12 g/mol) + 4 hydrogen atoms (4 × 1 g/mol) = 12 + 4 = 16 g/mol.
4. For NH\_3, calculate molar mass as: 1 nitrogen atom (14 g/mol) + 3 hydrogen atoms (3 × 1 g/mol) = 14 + 3 = 17 g/mol.
5. For H\_2O, calculate molar mass as: 2 hydrogen atoms (2 × 1 g/mol) + 1 oxygen atom (16 g/mol) = 2 + 16 = 18 g/mol, and for CO\_2, calculate molar mass as: 1 carbon atom (12 g/mol) + 2 oxygen atoms (2 × 16 g/mol) = 12 + 32 = 44 g/mol. Then arrange the compounds from smallest to largest molar mass based on these values.