What is the molar mass of C6H6 ?
The correct answer and explanation is:
The molar mass of C₆H₆ (benzene) is calculated by summing the molar masses of all the atoms in the molecular formula.
Step 1: Identify the atoms and their quantities
- Carbon (C): 6 atoms
- Hydrogen (H): 6 atoms
Step 2: Use atomic masses
- Atomic mass of Carbon (C) ≈ 12.01 g/mol
- Atomic mass of Hydrogen (H) ≈ 1.008 g/mol
Step 3: Calculate total molar mass
Molar mass of C6H6=(6×12.01)+(6×1.008)\text{Molar mass of C}_6\text{H}_6 = (6 \times 12.01) + (6 \times 1.008) =72.06+6.048=78.108 g/mol= 72.06 + 6.048 = 78.108 \text{ g/mol}
Answer: The molar mass of benzene (C₆H₆) is approximately 78.11 g/mol.
Explanation (300 words):
The molar mass of a compound is the mass of one mole of its molecules, expressed in grams per mole (g/mol). It is calculated by adding the atomic masses of all atoms present in the molecular formula. Benzene (C₆H₆) is a simple aromatic hydrocarbon composed of six carbon atoms and six hydrogen atoms.
Each carbon atom has an atomic mass close to 12.01 g/mol, reflecting the average atomic weight of carbon isotopes found naturally. Each hydrogen atom has an atomic mass near 1.008 g/mol. To find the molar mass of benzene, you multiply the number of atoms of each element by its atomic mass and sum these values.
The calculation steps are straightforward: 6 carbons times 12.01 g/mol plus 6 hydrogens times 1.008 g/mol. The result, about 78.11 g/mol, represents the mass of one mole of benzene molecules. This value is crucial in chemistry because it allows conversion between the amount of substance (in moles) and mass (in grams).
Knowing the molar mass is essential for many practical purposes. For example, in chemical reactions, stoichiometry calculations require molar masses to relate masses of reactants and products. In laboratory settings, the molar mass helps determine how much of a substance to weigh out to obtain a specific number of moles.
Benzene’s molar mass also relates to its physical properties, such as density and boiling point, which are important in industrial applications and safety considerations. Since benzene is a common solvent and a fundamental molecule in organic chemistry, understanding its molar mass forms a basic foundation for further study and experimentation.
In summary, calculating molar mass involves using atomic masses and the molecular formula to quantify the mass of one mole of molecules, a fundamental step in many chemical calculations and applications.