Hemoglobin is a protein that carries oxygen in the blood. It absorbs light stron

Question

Hemoglobin is a protein that carries oxygen in the blood. It absorbs light strong at a wavelength of 400 nm, which gives blood its red color. A solution of hemoglobin is diluted to 10 times its original volume (1.0 mL hemoglobin + 9.0 mL water). The diluted solution has an absorbance value of 0.354. a) Determine the absorbance value of the original solution. Explain how you arrived at your answer. b) It would be simpler to measure the absorbance of the original solution directly. Explain why it is better to dilute the solution before measuring the absorbance for this sample. Why is it important not to touch the sides of the cuvette with your fingers?

Explanation / Answer

a}Absorbance of diluted solution of heamoglobin ( 1mL heamoglobin in 10 ml solution) i.e 10% = 0.354

thus, original solution i.e 100% concentration = 0.354*100/10 =3.54

b} Its better to dilute the original solution before measuring the absorbance of a sample having higher concentration. So to allow a significant amount of light to pass through the solution which can be measured by the recorder. Substances whose absorption is very large may have to be diluted in order for significant light to reach the recorder.

Beer's law relates the concept of concentration and absorbance. According to this law, absorbance and concentration are directly proportional. If we increase the original concentration, the absorbance increases and if we dilute the solution(which means you decrease the original concentration), the absorbance will decrease in direct proportion.

c} it is important to not touch the sides of cuvette with your fingers because the residue or fingerprints does not remain on the cuvette which may hinder the light wave passing through the sample.this in turn may cause error in measurement of absorbance.

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