Question

please answer, this is all information 6.8 Several standard solutions of copper were prepared. These were aspirated into a flame and the absorp- tion measured with the following results. Prepare a calibration curve from the data. Absorbance Sample Concentration (ppm) Blank (0.0) 0.5 1.0 1.5 0.002 0.045 0.090 0.135 0.180 0.225 0.270

Answer 1

According to the Lambert-Beer Law,

$A=\epsilon bC$

So, when C is zero then, A should be zero. That is why to estimate the actual result we set the absorbance of the blank at '0'.

Concentration (ppm)	Absorbance (given)	Absorbance (actual) = given - Ablank
0.0	0.002	0
0.5	0.045	0.043
1.0	0.090	0.088
1.5	0.135	0.133
2.0	0.180	0.178
2.5	0.225	0.223
3.0	0.270	0.268

The plotting of these data is:

1 Absorbance 0.3+ 0.25+ 0.15+ 0.1+ 0.05+ Conc of Cu(ppm)

Line equation is: y = 0.0891*x + 0 ; R²=0.9999