To calculate the expected absorbance of a solution, we can use the Beer-Lambert Law, which states that the absorbance (A) of a solution is directly proportional to its concentration (c) and the path length (l), and is given by the formula:

A = εlc

where:
ε is the molar absorptivity (also known as the molar absorption coefficient),
l is the path length through which the light passes, and
c is the concentration of the solution.

In this case, we are given:
ε = 2100 M^-1 cm^-1,
l = 1 cm (assuming a standard cuvette is used), and
c = 20 mg/L.

However, the concentration needs to be in moles per liter (M) for the formula to work. So, we first need to convert the concentration from mg/L to M. We know that the molar mass (Mwt) of potassium permanganate is 158 g/mol, so:

c = 20 mg/L * (1 g/1000 mg) * (1 mol/158 g) = 0.000126582 M

Now we can substitute the values into the Beer-Lambert Law:

A = εlc
A = (2100 M^-1 cm^-1)(1 cm)(0.000126582 M)
A = 0.2656

Rounding to two significant figures, the expected absorbance of the solution is 0.27. So, the correct answer is A. 0.27.

Question

To calculate the expected absorbance of a solution, we can use the Beer-Lambert Law, which states that the absorbance (A) of a solution is directly proportional to its concentration (c) and the path length (l), and is given by the formula:

A = εlc

where:
ε is the molar absorptivity (also known as the molar absorption coefficient),
l is the path length through which the light passes, and
c is the concentration of the solution.

In this case, we are given:
ε = 2100 M^-1 cm^-1,
l = 1 cm (assuming a standard cuvette is used), and
c = 20 mg/L.

However, the concentration needs to be in moles per liter (M) for the formula to work. So, we first need to convert the concentration from mg/L to M. We know that the molar mass (Mwt) of potassium permanganate is 158 g/mol, so:

c = 20 mg/L * (1 g/1000 mg) * (1 mol/158 g) = 0.000126582 M

Now we can substitute the values into the Beer-Lambert Law:

A = εlc
A = (2100 M^-1 cm^-1)(1 cm)(0.000126582 M)
A = 0.2656

Rounding to two significant figures, the expected absorbance of the solution is 0.27. So, the correct answer is A. 0.27.

Knowee AI · Accepted Answer

To calculate the expected absorbance of a solution, we can use the Beer-Lambert Law, which states that the absorbance (A) of a solution is directly proportional to its concentration (c) and the path length (l), and is given by the formula:

A = εlc

where:
ε is the molar absorptivity (also known as the molar absorption coefficient),
l is the path length through which the light passes, and
c is the concentration of the solution.

In this case, we are given:
ε = 2100 M^-1 cm^-1,
l = 1 cm (assuming a standard cuvette is used), and
c = 20 mg/L.

However, the concentration needs to be in moles per liter (M) for the formula to work. So, we first need to convert the concentration from mg/L to M. We know that the molar mass (Mwt) of potassium permanganate is 158 g/mol, so:

c = 20 mg/L * (1 g/1000 mg) * (1 mol/158 g) = 0.000126582 M

Now we can substitute the values into the Beer-Lambert Law:

A = εlc
A = (2100 M^-1 cm^-1)(1 cm)(0.000126582 M)
A = 0.2656

Rounding to two significant figures, the expected absorbance of the solution is 0.27. So, the correct answer is A. 0.27.

alculate the expected absorbance of a 20mg/L solution of potassium permanganate at 525nm. Note the Mwt of potassium permanganate is 158 g/mol and assumethe molar absorptivity at 525nm is 2100 M-1 cm-1. Round answer to 2 sf.Selected Answer: [None Given]Answers: A. 0.27B. 0.42C. 0.21D. 0.50E. 0.84

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