What is the molar mass of ethanol (C2H6O)?
The Correct Answer and Explanation is:
The molar mass of ethanol (C₂H₆O) is 46.07 grams per mole (g/mol).
Explanation:
To calculate the molar mass of ethanol, we need to add up the atomic masses of each element in its molecular formula, C₂H₆O. The atomic masses of the constituent elements are as follows:
- Carbon (C): 12.01 g/mol
- Hydrogen (H): 1.008 g/mol
- Oxygen (O): 16.00 g/mol
Ethanol contains:
- 2 carbon atoms
- 6 hydrogen atoms
- 1 oxygen atom
Now multiply the atomic mass of each element by the number of atoms in the molecule:
- Carbon: 2 × 12.01 = 24.02 g/mol
- Hydrogen: 6 × 1.008 = 6.048 g/mol
- Oxygen: 1 × 16.00 = 16.00 g/mol
Add these values together to get the total molar mass of ethanol:
24.02 + 6.048 + 16.00 = 46.07 g/mol
Understanding molar mass is important in chemistry because it allows us to convert between the mass of a substance and the amount in moles. One mole of ethanol weighs 46.07 grams, which means that if you have 46.07 grams of ethanol, you have exactly one mole of ethanol molecules.
This calculation is vital for stoichiometric equations, which depend on the relationships between moles of reactants and products. For example, in combustion reactions or when calculating the amount of ethanol needed to react with another substance, you must know its molar mass to proceed with accurate conversions. Additionally, in lab settings, precise molar mass values help ensure that chemical reactions are carried out efficiently and safely, with the correct proportions of substances.
