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.