Question

In a spectrophotometric cell of 2. 0 cm path length, the solution of a substance shows an absorbance value of 1. 0. If the molar absorptivity of the compound is 2 x 10*L mol- 1 cm-1, calculate the concentration of the substance in solution. اختر احدي الدجابات 1. 0 x10* moll! 5. 0 x 10*moll' 4. 0 x10* mol L' 25x10moll"

Answer 1

Using the Beer-Lambert law, the concentration of the substance in solution is calculated to be 2.5 x 10^-4 mol L^-1, based on the given absorbance of 1.0, molar absorptivity of 2 x 10^3 L mol^-1 cm^-1, and a path length of 2.0 cm.

Step-by-step explanation:

To calculate the concentration of the substance in solution using the spectrophotometric data provided, we will apply the Beer-Lambert law, which is given by the equation Absorbance (A) = ε * c * l, where A is the absorbance, ε is the molar absorptivity, c is the concentration of the solution in moles per liter (M), and l is the path length in centimeters.

In the given scenario, the absorbance (A) is 1.0, the molar absorptivity (ε) is 2 x 103 L mol-1 cm-1, and the path length (l) is 2.0 cm. Plugging these values into the Beer-Lambert law, we get:

1.0 = (2 x 103 L mol-1 cm-1) * c * (2.0 cm)

To isolate the concentration (c), we rearrange the equation to solve for c:

c = 1.0 / (2 x 103 L mol-1 cm-1 * 2.0 cm)

c = 1.0 / (4 x 103 L mol-1)

c = 2.5 x 10-4 mol L-1

Therefore, the concentration of the substance in the solution is 2.5 x 10-4 mol L-1.