Question 1

&#8203;Nucleic acids absorb wavelengths between 250 and 300 nm,and hemoglobin absorbs wavelengths around 600 nm.This means that:&#10;A)&#8203;nucleic acids cannot absorb longer wavelengths as they are smaller than hemoglobin molecules are.&#10;B)&#8203;nucleic acids are more conjugated than hemoglobin is.&#10;C)&#8203;hemoglobin is more conjugated than nucleic acids are.&#10;D)&#8203;hemoglobin molecules can absorb higher wavelengths because they are bigger than nucleic acids are.

Accepted Answer

Hemoglobin absorbs longer wavelengths, around 600 nm, which means it is more conjugated than nucleic acids which absorb shorter wavelengths between 250 and 300 nm. The size of the molecules is not relevant to their ability to absorb different wavelengths.

Question 2

If the molar absorptivity of phthalocyanine is 162,000 L/( mol · cm),calculate the concentration of the compound in a solution placed in a cell of length 1-cm length and with a UV absorbance of 0.89.

A)4.49 x 10^-6 mol/L
B)5.49 x 10^-6 mol/L
C)6.49 x 10^-6 mol/L
D)7.49 x 10^-6 mol/L

Accepted Answer

We can use the Beer-Lambert law, which states that Absorbance = ε × l × c, where ε is the molar absorptivity, l is the path length (in this case, 1 cm), and c is the concentration.
Plugging in the given values, we get:
0.89 = 162,000 L/(mol·cm) × 1 cm × c
Solving for c, we get:
c = 0.89/162,000 mol/L = 5.49 × 10^−6 mol/L
Therefore, the answer is B.

Deck 14: Par 3