Determine the molar mass for ethanol, C2H6O.
The Correct Answer and Explanation is:
The molar mass of ethanol (C₂H₆O) is 46.07 grams per mole.
To calculate this, we add together the atomic masses of each element in the molecular formula:
- Carbon (C): 2 atoms × 12.01 g/mol = 24.02 g/mol
- Hydrogen (H): 6 atoms × 1.008 g/mol = 6.048 g/mol
- Oxygen (O): 1 atom × 16.00 g/mol = 16.00 g/mol
Now, summing them up:
24.02 + 6.048 + 16.00 = 46.07 g/mol
Explanation
The molar mass of a compound is the mass of one mole of its molecules. It is expressed in grams per mole and calculated by adding the atomic masses of all the atoms in a molecule. These atomic masses can be found on the periodic table and are based on the average masses of the isotopes of each element.
Ethanol is a simple organic compound with the molecular formula C₂H₆O. This tells us it contains two carbon atoms, six hydrogen atoms, and one oxygen atom. To find the molar mass of ethanol, we multiply the number of atoms of each element by that element’s atomic mass and then sum the results.
Carbon has an atomic mass of approximately 12.01 g/mol. With two carbon atoms, we get 24.02 g/mol from carbon. Hydrogen has an atomic mass of about 1.008 g/mol, and with six hydrogen atoms, we get 6.048 g/mol. Oxygen contributes 16.00 g/mol since there is only one atom in the ethanol molecule.
When these values are added together, we get 46.07 grams per mole. This value is important in chemistry because it allows us to convert between the number of moles of ethanol and its mass in grams, which is essential for laboratory work, stoichiometric calculations, and preparing chemical solutions accurately.
