five ml of colored solution has an absorbance of .500nm The absorbance of 10ml of the same solution is.. 0.500nm

five ml of colored solution has an absorbance of .500nm The absorbance of 10ml of the same solution is?

  • A- 1.000nm
  • B- 0.250nm
  • C- 0.500nm

The correct answer is A. 1.000nm.

Here's why:
  • Beer-Lambert Law: This law states that the absorbance (A) of a solution is directly proportional to its concentration (c) and path length (l). It can be expressed as: A = ε * c * l, where ε is the molar absorptivity (a constant for a specific molecule at a specific wavelength).
  • Same Solution: Since it's the same colored solution, the molar absorptivity (ε) remains constant.
  • Double the Volume: Doubling the volume (from 5 ml to 10 ml) essentially halves the concentration (c).
  • Constant Path Length: Assuming the same cuvette is used for both measurements, the path length (l) remains constant.
Therefore, to maintain the same absorbance (A) with a halved concentration, the light needs to travel through twice the amount of solution. This doubles the product of c * l, resulting in an absorbance of 1.000 nm, which is double the original 0.500 nm.

Other Options:

Options B and C are incorrect because:
  • 0.250nm (B): This would be the absorbance if the concentration were halved and the path length remained the same. However, in this case, the path length doubles.
  • 0.500nm (C): This is the absorbance of the original 5 ml solution. Doubling the volume would double the absorbance.

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