Please help with calculating ppm

Question

This has to do with the calibration curve of Fe

the ppm = 1.04

the mL is 50.0

concentration of standard Fe = 259.7 ppm

absorbance =0.299 corrected absorbance = 0.278

I'm having trouble getting to the ppm of 1.04

I'm supposed to use the slope equation from the graph y= 0.2294x+ 0.0169 I tried plugging in the absorbance and got a different answer any advice or help?

Answer 1

I'm not entirely sure what you mean by "corrected absorbance". How was it corrected? Also, why are we given Fe = 259.7 ppm and 50 ml volume? Do we need these values? Are you providing us with the entire question? Having said that...

If the linear regression is y = 0.2294x + 0.0169, then you can use the corrected absorbance reading (0.278) to calculate the ppm (assuming ppm is plotted on the x-axis).

0.278 = 0.2294x + 0.0169

0.2294x = 0.2611

x = 1.138 = 1.14 (are you sure the answer isn't 1.14 and not 1.04?)