Which of the following is the correct molar mass of urea (NH2CONH2)?

• A. 18.02 g/mol
• B. 60.07 g/mol
• C. 28.05 g/mol
• D. 44.01 g/mol

Answer: (B)

Verified step by step guidance

1. Identify the molecular formula of urea, which is NH\_2CONH\_2. This means the molecule contains 1 carbon (C), 1 oxygen (O), 4 hydrogens (H), and 2 nitrogens (N).
2. Find the atomic masses of each element from the periodic table: Hydrogen (H) ≈ 1.01 g/mol, Carbon (C) ≈ 12.01 g/mol, Nitrogen (N) ≈ 14.01 g/mol, Oxygen (O) ≈ 16.00 g/mol.
3. Calculate the total mass contributed by each element by multiplying the atomic mass by the number of atoms in the formula: For example, for hydrogen, multiply 1.01 g/mol by 4.
4. Add all the individual masses together to get the molar mass of urea: Total molar mass = (number of C atoms × atomic mass of C) + (number of O atoms × atomic mass of O) + (number of N atoms × atomic mass of N) + (number of H atoms × atomic mass of H).
5. Compare the calculated molar mass with the given options to identify the correct molar mass of urea.