Calculate the molar mass of CH4 (atomic mass: H = 1, C = 12) 12 g/mol 14 g/mol 13 g/mol 16 g/mol
The Correct Answer and Explanation is:
To calculate the molar mass of methane (CH₄), we need to sum the atomic masses of all the elements in the molecule.
Step-by-step calculation:
- Carbon (C):
- There is 1 carbon atom in CH₄, and the atomic mass of carbon is 12 g/mol.
- So, the contribution of carbon to the molar mass is: 1×12 g/mol=12 g/mol1 \times 12 \, \text{g/mol} = 12 \, \text{g/mol}1×12g/mol=12g/mol
- Hydrogen (H):
- There are 4 hydrogen atoms in CH₄, and the atomic mass of hydrogen is 1 g/mol.
- So, the contribution of hydrogen to the molar mass is: 4×1 g/mol=4 g/mol4 \times 1 \, \text{g/mol} = 4 \, \text{g/mol}4×1g/mol=4g/mol
Total Molar Mass of CH₄: 12 g/mol+4 g/mol=16 g/mol12 \, \text{g/mol} + 4 \, \text{g/mol} = 16 \, \text{g/mol}12g/mol+4g/mol=16g/mol
So, the correct molar mass of CH₄ is 16 g/mol.
Why this is the correct answer:
The molar mass of a molecule is determined by adding the atomic masses of each element it contains. The atomic mass of carbon is 12 g/mol, and each hydrogen atom contributes 1 g/mol. By adding the contributions from carbon and hydrogen, we get the total molar mass of CH₄ as 16 g/mol.
This is the standard molar mass for methane, which is a common simple molecule and often appears in chemistry calculations, particularly those related to combustion and gas laws.
