The molecular mass of sucrose is determined by adding up the atomic masses of all the atoms in its chemical formula, C₁₂H₂₂O₁₁.
Here's a breakdown of how to calculate it, incorporating the information provided in the reference:
Understanding Molecular Mass
Molecular mass, often referred to as molecular weight, is the sum of the atomic masses of all the atoms in a molecule. It is expressed in atomic mass units (amu). The molar mass is the mass of one mole of a substance and is numerically equivalent to the molecular mass, but expressed in grams per mole (g/mol).
Calculation Steps
-
Identify the Chemical Formula: The chemical formula for sucrose is C₁₂H₂₂O₁₁. This means it has 12 carbon atoms, 22 hydrogen atoms, and 11 oxygen atoms.
-
Obtain Atomic Masses: You'll need the atomic masses of each element from the periodic table:
- Carbon (C): approximately 12.01 amu
- Hydrogen (H): approximately 1.01 amu
- Oxygen (O): approximately 16.00 amu
-
Multiply and Add: Multiply the atomic mass of each element by the number of atoms of that element in the formula, then add the results together:
(12 x 12.01 amu) + (22 x 1.01 amu) + (11 x 16.00 amu) = Total molecular mass.
- Carbon: 12 atoms * 12.01 amu/atom = 144.12 amu
- Hydrogen: 22 atoms * 1.01 amu/atom = 22.22 amu
- Oxygen: 11 atoms * 16.00 amu/atom = 176.00 amu
-
Calculate the Total: 144.12 amu + 22.22 amu + 176.00 amu = 342.34 amu. This is the molecular mass of a single sucrose molecule.
-
Molar Mass: As highlighted in the reference, the molar mass of sucrose (C₁₂H₂₂O₁₁) is numerically equal to the molecular mass but with units of g/mol. Therefore, the molar mass of sucrose is approximately 342 g/mol.
Key Takeaway from the Reference:
The reference explicitly states that the molar mass of C₁₂H₂₂O₁₁ is 342 g/mol. This confirms our calculated result based on adding individual atomic masses. The reference shows that M 0 = 342 g/mol, where M 0 is the molar mass, a real number that's numerically the same as the atomic mass.
Summary
The molecular mass of sucrose is approximately 342.34 amu. The molar mass is approximately 342 g/mol. The molar mass of a substance (in gram per mole) is equal (in numbers) to the mass of its single atom/molecule/ion when expressed in unified atomic mass units.
