Final answer:
The molar mass of a compound is the sum of the atomic masses of all the atoms in the molecular formula or formula unit of the compound. To find the number of moles of a compound in a known mass of the compound, divide the mass of the compound by its molar mass.
Step-by-step explanation:
The molar mass of a compound is the sum of the atomic masses of all the atoms in the molecular formula or formula unit of the compound. To find the number of moles of a compound in a known mass of the compound, we need to use its molecular formula and the molar mass. For example, let's say we have a compound with the molecular formula C4H10. The molar mass of carbon (C) is 12.01 g/mol, and the molar mass of hydrogen (H) is 1.008 g/mol. Therefore, the molar mass of the compound is (4x12.01) + (10x1.008) = 58.12 g/mol.
If we have a known mass of the compound, let's say 29.06 grams, we can calculate the number of moles by dividing the mass by the molar mass: 29.06 g / 58.12 g/mol = 0.5 mol.
So, to determine the number of moles of a compound in a known mass of the compound, divide the mass of the compound by its molar mass.