Can someone please explain to me how to do this question I've tried it many times and failed, I currently can't do any of these type of questions but if i find out the method I should learn how to do them.
In order to measure the concentration of mercury in sea water near an industrial plant, a team of chemsits used AAS. They first calibrated their instrument by admitting some standard solutions to it and determining the absorbance for each. They then measured the absorbance level of several water samples collected from different locations near the industrial plant. For their standards they made a stock solution by dissolving 0.106g mercury [as mercury (II) nitrate] in water and making the volume to 250mL in a volumetric flask, then they quantitatively diluted (by pitette) 1mL, 2mL and 4mL of this solution to 100mL (volumetric flask). Absorbances for the standards and the samples are shown below.
Standards (ml) Absorbance
1 0.083
2 0.164
4 0.331
Samples Absorbance
A 0.32
B 0.46
C 0.21
D 0.055
Draw a calibration curve of absorbance versus concentration in parts per million (ppm) for the standards. Take 1.00mL of aqueous solution as 1.00g. Determine the concentration of mercury (in ppm) in each of the samples.
What I did which turned out wrong was to put the weight of mercury of that of Hg(NO3)2 and find the amount of mercury in the 0.106g sample. So 200.6/312.61 x 0.106 = 0.0680g mercury. Then divided that by 250 to get 2.72mg/L
so thats 2.72ppm in 1ml
5.44ppm in 2ml
10.88ppm in 4ml I drew the calibration curve and what not and still got it wrong. Please help me and let me know what mistakes im making? or what im not doing. Thanks
)
In order to measure the concentration of mercury in sea water near an industrial plant, a team of chemsits used AAS. They first calibrated their instrument by admitting some standard solutions to it and determining the absorbance for each. They then measured the absorbance level of several water samples collected from different locations near the industrial plant. For their standards they made a stock solution by dissolving 0.106g mercury [as mercury (II) nitrate] in water and making the volume to 250mL in a volumetric flask, then they quantitatively diluted (by pitette) 1mL, 2mL and 4mL of this solution to 100mL (volumetric flask). Absorbances for the standards and the samples are shown below.
Standards (ml) Absorbance
1 0.083
2 0.164
4 0.331
Samples Absorbance
A 0.32
B 0.46
C 0.21
D 0.055
Draw a calibration curve of absorbance versus concentration in parts per million (ppm) for the standards. Take 1.00mL of aqueous solution as 1.00g. Determine the concentration of mercury (in ppm) in each of the samples.
What I did which turned out wrong was to put the weight of mercury of that of Hg(NO3)2 and find the amount of mercury in the 0.106g sample. So 200.6/312.61 x 0.106 = 0.0680g mercury. Then divided that by 250 to get 2.72mg/L
so thats 2.72ppm in 1ml
5.44ppm in 2ml
10.88ppm in 4ml I drew the calibration curve and what not and still got it wrong. Please help me and let me know what mistakes im making? or what im not doing. Thanks
)