The molecular weight (molar mass) of KMnO₄ (potassium permanganate) is calculated by adding the atomic masses of all its constituent elements.
Step-by-Step Calculation:
- Potassium (K) = 39 g/mol
- Manganese (Mn) = 55 g/mol
- Oxygen (O) = 16 g/mol × 4 = 64 g/mol
Total Molecular Weight:
39 + 55 + 64 = 158 g/mol
Final Answer:
- Molecular weight of KMnO₄ = 158 g/mol
Key Insight:
- Always multiply the atomic mass of oxygen by 4, as there are four oxygen atoms in KMnO₄.
Applications of KMnO₄:
- Used as a strong oxidizing agent in chemistry
- Used in water purification
- Acts as a disinfectant
Exam Tip:
- Write atomic masses clearly and show calculation steps to score full marks.