The molar mass of phosphorus pentachloride (PCl5) can be calculated by adding the atomic masses of its constituent elements. Phosphorus has an atomic mass of approximately 31.00 g/mol, and chlorine has an atomic mass of about 35.45 g/mol. Since there are five chlorine atoms in phosphorus pentachloride, we multiply the atomic mass of chlorine by 5.
The calculation is as follows:
- Phosphorus: 1 × 31.00 g/mol = 31.00 g/mol
- Chlorine: 5 × 35.45 g/mol = 172.25 g/mol
Next, we sum these values:
Total: 31.00 g/mol + 172.25 g/mol = 203.25 g/mol
Therefore, the molar mass of phosphorus pentachloride is approximately 203.25 g/mol.