Calculate the mass percentage of aspirin `(C_(9)H_(8)O_(4))` in acetonitrile `(CH_(3)CN)` when 6.5 g of `C_(9)H_(8)O_(4)` is dissolved in 450 g of `CH_(3)CN`.

Explanation

To calculate the mass percentage of aspirin (C₉H₈O₄) in acetonitrile (CH₃CN), we can follow these steps:

### Step 1: Identify the mass of the solute and solvent
- The mass of aspirin (solute) is given as 6.5 g.
- The mass of acetonitrile (solvent) is given as 450 g.

### Step 2: Calculate the total mass of the solution
- The total mass of the solution is the sum of the mass of the solute and the mass of the solvent.

\[ \text{Total mass of solution} = \text{mass of aspirin} + \text{mass of acetonitrile} \]

\[ \text{Total mass of solution} = 6.5 \, \text{g} + 450 \, \text{g} = 456.5 \, \text{g} \]

### Step 3: Use the mass percentage formula
- The formula for mass percentage is:

\[ \text{Mass percentage of aspirin} = \left( \frac{\text{mass of solute}}{\text{total mass of solution}} \right) \times 100\% \]

### Step 4: Substitute the known values into the formula
- Substitute the mass of aspirin and the total mass of the solution into the formula:

\[ \text{Mass percentage of aspirin} = \left( \frac{6.5 \, \text{g}}{456.5 \, \text{g}} \right) \times 100\% \]

### Step 5: Calculate the mass percentage
- Perform the calculation:

\[ \text{Mass percentage of aspirin} = \left( \frac{6.5}{456.5} \right) \times 100\% \approx 1.42\% \]

### Final Answer
- The mass percentage of aspirin in acetonitrile is approximately **1.42%**.

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