To calculate the molar mass of a chemical compound, you need to determine the sum of the atomic masses of all the atoms in the compound. Here are the steps to calculate molar mass:
Write down the chemical formula of the compound. Make sure you know the correct formula with the correct subscripts for each element.
Look up the atomic masses of each element in the periodic table. The atomic mass is usually expressed in atomic mass units (u) or grams per mole (g/mol).
Identify the number of atoms of each element in the compound from the chemical formula. The subscripts in the formula indicate the number of atoms of each element. If there is no subscript, it is assumed to be 1.
Multiply the atomic mass of each element by the number of atoms of that element in the compound.
Sum up all the products obtained in step 4 to calculate the molar mass of the compound.
Here’s an example:
Let’s calculate the molar mass of water (H2O).
Chemical formula: H2O
Atomic masses:
Hydrogen (H) atomic mass = 1 g/mol
Oxygen (O) atomic mass = 16 g/mol
Number of atoms:
Hydrogen (H) = 2
Oxygen (O) = 1
Calculate the mass contribution of each element:
Hydrogen (H): 2 atoms * 1 g/mol = 2 g/mol
Oxygen (O): 1 atom * 16 g/mol = 16 g/mol
Sum up the contributions: Molar mass of water (H2O) = 2 g/mol + 16 g/mol = 18 g/mol
So, the molar mass of water (H2O) is 18 grams per mole (g/mol).
You can follow these steps for any chemical compound to calculate its molar mass. Remember to use accurate atomic masses from the periodic table and pay attention to the subscripts in the chemical formula.