The molecular mass of water (H₂O) is calculated by summing the atomic weights of all atoms in the molecule.
Here's a breakdown of how to do it, based on the provided reference:
Calculating Molecular Mass of H2O
According to the periodic table, we find the following atomic weights:
- Hydrogen (H) has an atomic weight of 1.
- Oxygen (O) has an atomic weight of 16.
A water molecule (H₂O) consists of two hydrogen atoms and one oxygen atom. Therefore, to calculate the molecular mass of water, we perform the following calculation:
| Atom | Number of Atoms | Atomic Weight | Calculation |
|---|---|---|---|
| Hydrogen (H) | 2 | 1 | 2 x 1 = 2 |
| Oxygen (O) | 1 | 16 | 1 x 16 = 16 |
| Total | 2 + 16 = 18 |
Therefore, the molecular mass of one water molecule is 18 grams/mole.
Key Takeaways
- Atomic weights are used to calculate molecular mass.
- Multiply the atomic weight of each element by the number of atoms of that element in the molecule.
- Sum up these products to get the total molecular mass.
