Consider an unknown solution that contains compound A in a solvent that has an absorbance of 0.029 at 238 nm.
If the absorbance of  compound A in a 1 cm cuvette is 0.375 at 238 nm, then the concentration of compound A = 
blank2 - Numeric Answer

M.
If the concentration of compound A is 3.96 x 10^{-4} M and it has an absorbance of 0.595 at 238 nm in a 1.00 cm cuvette, then the molar absorptivity of compound A = 
blank1 - Numeric Answer

A sample of the unknown solution is now diluted from an initial volume of 2.00 mL to a final volume of 25.00  mL. If the diluted solution has an absorbance of 0.73 x 10^3 then the concentration of A in the initial solution is

To solve these questions, let's tackle each part step by step:

### Part 1: Calculating Molar Absorptivity (ε)
Given:
- **Concentration** (\(C\)) = \(3.96 \times 10^{-4} \, M\)
- **Absorbance** (\(A\)) = 0.595
- **Path length** (\(l\)) = 1.00 cm

We can use the Beer-Lambert Law:
\[
A = \epsilon \cdot C \cdot l
\]

Rearrange to solve for molar absorptivity (\(\epsilon\)):
\[
\epsilon = \frac{A}{C \cdot l} = \frac{0.595}{(3.96 \times 10^{-4}) \times 1.00}
\]

Calculating this:
\[
\epsilon = \frac{0.595}{3.96 \times 10^{-4}} \approx 1503.79 \, \text{M}^{-1}\text{cm}^{-1}
\]

So, **Blank 1 = 1503.79 M\(^{-1}\)cm\(^{-1}\)**.

---

### Part 2: Concentration of Compound A in Unknown Solution
Given:
- **Absorbance of Compound A in Unknown Solution** = 0.375
- **Path length** (\(l\)) = 1.00 cm
- **Molar absorptivity** (\(\epsilon\)) = 1503.79 M\(^{-1}\)cm\(^{-1}\) (from Part 1)

Using Beer-Lambert Law again:
\[
A = \epsilon \cdot C \cdot l
\]

Rearrange to solve for concentration (\(C\)):
\[
C = \frac{A}{\epsilon \cdot l} = \frac{0.375}{1503.79 \times 1.00}
\]

Calculating this:
\[
C \approx 2.49 \times 10^{-4} \, M
\]

So, **Blank 2 = 2.49 \times 10^{-4} \, M**.

---

### Part 3: Concentration of Compound A in Initial Solution Before Dilution
Given:
- **Dilution from initial volume** = 2.00 mL to **final volume** = 25.00 mL
- **Absorbance of diluted solution** = 0.73
- **Path length** (\(l\)) = 1.00 cm
- **Molar absorptivity** (\(\epsilon\)) = 1503.79 M\(^{-1}\)cm\(^{-1}\) (from Part 1)

1. **Calculate the concentration of A in the diluted solution** using Beer-Lambert Law:
   \[
   C_{\text{diluted}} = \frac{A}{\epsilon \cdot l} = \frac{0.73}{1503.79 \times 1.00}
   \]

   Calculating this:
   \[
   C_{\text{diluted}} \approx 4.86 \times 10^{-4} \, M
   \]

2. **Determine concentration in the initial solution**:
   Since the solution was diluted from 2.00 mL to 25.00 mL, we can use the dilution formula:
   \[
   C_{\text{initial}} = C_{\text{diluted}} \times \frac{\text{final volume}}{\text{initial volume}}
   \]

   Substituting the values:
   \[
   C_{\text{initial}} = (4.86 \times 10^{-4}) \times \frac{25.00}{2.00}
   \]

   Calculating this:
   \[
   C_{\text{initial}} \approx 6.08 \times 10^{-3} \, M
   \]

So, the **concentration of A in the initial solution is approximately \(6.08 \times 10^{-3} \, M\)**.

---

### Summary of Answers:
- **Blank 1 (Molar Absorptivity)** = \(1503.79 \, \text{M}^{-1}\text{cm}^{-1}\)
- **Blank 2 (Concentration of Compound A)** = \(2.49 \times 10^{-4} \, M\)
- **Initial Concentration of Compound A** = \(6.08 \times 10^{-3} \, M\)

Would you like more details on any part, or do you have questions?

---

### Related Questions:
1. What factors affect the accuracy of the molar absorptivity calculation?
2. How does path length influence absorbance readings?
3. What is the significance of the Beer-Lambert Law in spectrophotometry?
4. How would changes in solvent concentration impact absorbance?
5. Can absorbance values indicate the purity of a solution?

**Tip:** Always check if your cuvette path length matches the setup assumptions, as even small discrepancies can impact absorbance calculations.

Consider an unknown solution that contains compound A in a solvent that has an absorbance of 0.029 at 238 nm. If the absorbance of compound A in a 1 cm cuvette is 0.375 at 238 nm, then the concentration of compound A = blank2 - Numeric Answer M. If the concentration of compound A is 3.96 x 10^{-4} M and it has an absorbance of 0.595 at 238 nm in a 1.00 cm cuvette, then the molar absorptivity of compound A = blank1 - Numeric Answer. A sample of the unknown solution is now diluted from an initial volume of 2.00 mL to a final volume of 25.00 mL. If the diluted solution has an absorbance of 0.73 x 10^3 then the concentration of A in the initial solution is.

Learn to calculate molar absorptivity and initial concentration of compound A in an unknown solution using Beer-Lambert Law and dilution formulas. This problem explores spectrophotometry, absorbance, and solution dilution calculations, with absorbance measurements at 238 nm in a 1 cm cuvette.

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