Question

Score pts Use the internet to determine what compounds used commonly in fireworks give specific colors, list three compounds and the corresponding colors. Compound Color Stranium carbonate copper Chlonde blue Calcium chloride - OYOnDe red What are the energies () and wavelengths (in nm) for these colors? Color Energy wavelength red 700 nm orange 500nm blue Soonm ,2. (5 pts) Use the data provided below to prepare a Beer's law plot in Excel. Plot absorbance on the y axis and concentration on the x axis. Add a trend line to your linear graph. Use your graph to determine the concentration of a sample measured to have and absorbance value of 0.35 absorbance units. Show on your graph how you determine the concentration of the unknown. Turn in your graph. Concentration (M) Absorbance (A) 0.20 0.27 0.30 0.41 0.40 0.55 0.50 0.69 Unknown concentration from graphical analysis

Answer 1

The relation between wavelength and energy is -

$E=\frac{h\times c}{\lambda }$

h = Planck's Constant=6.626*10^-34 J sec

c = velocity of light = 3*10⁸ m sec^-1
Using this relation and wavelengths  , we can find energy . The values will be -

Color	Wavelength($\lambda$)	Energy($E$)
Red	680 nm	2.923*10-19 J
Orange	600 nm (av)	3.313*10-19 J
Blue	420 nm (av)	4.733*10-19 J

The plot will be -

The unknown concentration from graphical analysis reveals 0.2547 M . [ANSWER]

Absorbance 1-+ 0.8 0.6 0.4 0.2 Concentration (M) 0'9 0.25 0.55 o's 0.05 02 0.3 0.35 0.65 0.85 0.95 0.45 0.6 0.15 0.4 0.5 0.75 0.7 0.2547 M -0.2