To calculate the formula weight or molecular mass of potassium chromate (K₂CrO₄), we need to sum the atomic masses of all the atoms in the formula based on the periodic table.
1. **Identify the elements in K₂CrO₄**: Potassium (K), Chromium (Cr), and Oxygen (O).
2. **Find the atomic masses** (approximately):
- Potassium (K): 39.10 g/mol
- Chromium (Cr): 51.99 g/mol
- Oxygen (O): 16.00 g/mol
3. **Calculate the total mass**:
- For Potassium: 2 x 39.10 g/mol = 78.20 g/mol
- For Chromium: 1 x 51.99 g/mol = 51.99 g/mol
- For Oxygen: 4 x 16.00 g/mol = 64.00 g/mol
4. **Sum the masses**:
Total Molecular Mass = 78.20 g/mol + 51.99 g/mol + 64.00 g/mol = 194.19 g/mol
Therefore, the formula weight (molecular mass) of potassium chromate (K₂CrO₄) is 194.19 g/mol.