Question

The absorbance of a blue-colored 0.008 M Cu2+ solution was measured throughout the visible region of the electromagnetic spectrum. The spectrophotometer was then set at Amax and the absorbance was measured for several solutions of various Cu2+ concentrations. Graph A: Amax = 620 nm Amax = 620 0.800 0.700 0.600 0.500 Graph B: y = 80.6 x -0.005 0.900 0.800 0.700 0.600 0.500 0.400 0.300 0.200 0.100 0.000 0.0000 0.0050 0.0100 0.400 0.300 0.200 0.100+ 0.000 400 450 500 550 600 650 700 750 800 0.0150

View the attachment and answer the following questions:

A. The Beer's law relationship was established by measuring the absorbance of:

A) Several solutions at one wavelength.

B) One solution at several wavelengths.

C) Several solutions over a range of wavelengths.

D) One solution at one wavelength.

B. The y-intercept in Graph B has:

A) 3 decimal places because the Spec 20 displayed 3 decimal places for each reading.

B) 3 decimal places because there are 3 significant figures in the slope of the line.

C) 1 significant figure because the y-axis labels have only 1 significant figure.

D) 1 significant figure because the slope of the line has only 1 decimal place.

C. Graph B indicates that:

A) The measured absorbance for a solution is nearly zero when the concentration is zero.

B) The measured absorbance for a solution increases with increasing wavelength at a rate of approximately 81 times the initial absorbance.

C) To a close approximation, when the concentration of the solution doubles, the absorbance doubles.

D) Both A and C are correct

E) Both B and C are correct

Answer 1

a) Several Solutions at One Wardlength. That Wavelength is domar. As ber Beers law . I t Absbane loj I = Cal 1 (= Concentration I ALC So Different Solutions of different concertation are taken. (A) 2 decimal place because the Hospec 20 has diplayed 3 decimal Places for each Reading. Ans D Both A and Care Corrett A ler Beerle Law - A= Ecd So A=0 When cao - so othin Air Cred - When (=20 A will be 2A - so ottion Conect. is