The absorbance of a chlorophyll a standard solution in ethanol (density = 0.785 g/mL) is measured in

a 1.3 cm cuvette or path length. The absorbance is 0.765 and the molar absorptivity coefficient is 86,300 M-1cm-1.

The molecular weight for chlorophyll a is 893.49 g/mol.

What is the concentration of the solution in ppm?

Question

Chemistry

Francesca Salazar

29 May, 01:46

The absorbance of a chlorophyll a standard solution in ethanol (density = 0.785 g/mL) is measured in

a 1.3 cm cuvette or path length. The absorbance is 0.765 and the molar absorptivity coefficient is 86,300 M-1cm-1.

The molecular weight for chlorophyll a is 893.49 g/mol.

What is the concentration of the solution in ppm?

+2

Answers (1)

Know the Answer?

Mitchell Zavala · Answer 1

Let A = ebc

0.765 = 86,300*1.3*c

Solve for c = approximately 7E-6 Molar

= mols/L soln.

g = 7E-6*893.49

= about 0.006 g chlorophyll/L soln.

1000 x 0.785 = 785 g ethanol.

Conc. = about 0.006g chlorophyll/785 g soln.

Change that to ppm. by using formula:

(0.006/785) * 1E6