```
A solution of a dye has an absorbance of 1.2 at its λmax of 450 nm. After diluting the
solution by a factor of 5, the absorbance is measured to be 0.24. Verify if the dilution was
performed correctly and calculate the concentration of the original solution if the molar
absorptivity is 25000 L/(mol·cm) and the path length is 1 cm.
```

Sign in to unlock the answer

Answer from Sia

Posted 4 months ago

Answer

The dilution was performed correctly, and the concentration of the original solution is 0.048 M.

Solution

a

Use Beer's Law: $A = \epsilon \cdot c \cdot l$, where $A$ is absorbance, $\epsilon$ is molar absorptivity, $c$ is concentration, and $l$ is path length

b

Calculate the concentration of the diluted solution: $c_{\text{diluted}} = \frac{A_{\text{diluted}}}{\epsilon \cdot l} = \frac{0.24}{25000 \cdot 1} = 9.6 \times 10^{-6} \text{ M}$

c

Verify the dilution factor: $c_{\text{original}} = c_{\text{diluted}} \times \text{dilution factor} = 9.6 \times 10^{-6} \times 5 = 4.8 \times 10^{-5} \text{ M}$

d

Calculate the concentration of the original solution: $c_{\text{original}} = \frac{A_{\text{original}}}{\epsilon \cdot l} = \frac{1.2}{25000 \cdot 1} = 4.8 \times 10^{-5} \text{ M}$

Key Concept

Beer's Law

Explanation

Beer's Law relates the absorbance of a solution to its concentration, molar absorptivity, and path length. By using this law, we can verify the dilution and calculate the concentration of the original solution.

Not the question you are looking for? Ask here!

Enter question by text

Enter question by image

Upgrade to Asksia Pro

Join a AskSia's Pro Plan, and get 24/7 AI tutoring for your reviews, assignments, quizzes and exam preps.

Unlimited chat query usages

Strong algorithms that better know you

Early access to new release features

Study Other Question