Calculate the number of moles in 474 grams of ` KMnO_4`

Answer

To calculate the number of moles in 474 grams of KMnO4, we can follow these steps:

### Step 1: Determine the Molar Mass of KMnO4
To find the molar mass, we need to sum the atomic masses of all the elements in the compound KMnO4.

- Potassium (K): 39 g/mol
- Manganese (Mn): 55 g/mol
- Oxygen (O): 16 g/mol (and there are 4 oxygen atoms)

Now, we calculate the total molar mass:
\[ \text{Molar mass of KMnO}_4 = \text{Molar mass of K} + \text{Molar mass of Mn} + 4 \times \text{Molar mass of O} \]
\[ = 39 + 55 + (4 \times 16) \]
\[ = 39 + 55 + 64 \]
\[ = 158 \text{ g/mol} \]

### Step 2: Use the Formula to Calculate Moles
The number of moles (n) can be calculated using the formula:
\[ n = \frac{\text{Given mass}}{\text{Molar mass}} \]
Substituting the values we have:
\[ n = \frac{474 \text{ g}}{158 \text{ g/mol}} \]

### Step 3: Perform the Calculation
Now, we perform the division:
\[ n = \frac{474}{158} \approx 3 \]

### Conclusion
The number of moles in 474 grams of KMnO4 is approximately 3 moles.

---