A solution of 4-methyl-3-penten-2-one in ethanol shows an absorbance of 0.52 at 236 nm in a cell with a 1-cm light path. Its molar absorptivity in ethanol at that wavelength is 12,600 M^-1 cm^-1. What is the concentration of the compound?
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To calculate the concentration of the compound, we can use the Beer-Lambert Law, which relates the absorbance of a solution to the concentration of the absorbing species. The formula is:
A = ε * c * l
Where:
A = Absorbance
ε = Molar absorptivity (also known as molar extinction coefficient, in units of M^-1 cm^-1)
c = Concentration of the compound (in units of Molarity, or M)
l = Path length of the cuvette (in units of cm)
Given:
Absorbance (A) = 0.52
Molar absorptivity (ε) = 12,600 M^-1 cm^-1
Path length (l) = 1 cm
We can rearrange the Beer-Lambert Law formula to solve for the concentration (c):
c = A / (ε * l)
Let's substitute the given values into the equation:
c = 0.52 / (12,600 M^-1 cm^-1 * 1 cm)
Now, we can solve for the concentration:
c = 0.52 / 12,600 M^-1
c ≈ 0.000041 M
Therefore, the concentration of the compound is approximately 0.000041 M (Molarity).