[Emster]

I am lost for this one...

I have standards from phosphomolybdic acid that vary from 3 to 30 micrograms per cm cubic. I have the following information:
Slope = 0.425
Intercept = 0.015
Correl = 0.9995
Next, I have sample of 10ml of sea water that I need to analyze. The sample has been treated with the reagents and diluted to 25 ml. The absorbance of the sample is A=0.395 at a wavelenght of 600nm (1 cm wall). I need to find the concentration of the phosphates in the sample.

Any help would be appretiated. P.S. I don't have any more info, and I am doing this on paper, not in excel.

[chenbeier]

Do you know the Lambert-Beer Law.

You have standards and the parameters of the curve, so the Absorbance can be calculated.  For the analysis you calculate back from Absorbance to concentration

[Babcock_Hall]

Whenever I do dilution calculations, I draw a picture to help apply the dilution formula correctly.  I also use units in a consistent manner.  Many students run their ships aground in this calculation because of errors such as these.