To find the gram formula mass (also known as molar mass or molecular weight) of a compound, you need to follow these steps:
Determine the chemical formula of the compound: Identify the elements present in the compound and the number of atoms of each element.
Find the atomic masses: Look up the atomic masses of each element from the periodic table. The atomic mass represents the average mass of an atom of that element.
Multiply the atomic masses by the number of atoms: Multiply the atomic mass of each element by the number of atoms of that element in the compound.
Add the values: Sum up the products obtained from step 3.
The resulting sum will be the gram formula mass of the compound, expressed in grams per mole (g/mol). This value represents the mass of one mole of the compound.
Here's an example calculation for the gram formula mass of water (H2O):
- Chemical formula: H2O (2 hydrogen atoms, 1 oxygen atom)
- Atomic masses: Hydrogen (H) = 1.008 g/mol, Oxygen (O) = 15.999 g/mol
- Calculation: (2 * 1.008 g/mol) + (1 * 15.999 g/mol) = 2.016 g/mol + 15.999 g/mol = 18.015 g/mol
Therefore, the gram formula mass of water (H2O) is 18.015 g/mol.