Question

16. Tooth enamel consists mainly of the mineral calcium hydroxyapatite, Cao(PO).COH). elements in teeth of archeological specimens provide anthropologists with clues about diet and diseases of ancient people. Students at Hamline University measured the trace element strontium in enamel from extracted wisdom teeth by atomic absorption spectroscopy. Solutions were prepared with a constant total volume of 10.0 mL containing 0.750 mg dissolved tooth enamel plus variable concentrations of added Sr. X]i Is If + (s} Isrx Added Sr Signal (gm. - ppt) (arbitrary units) corrected signal 0.0 6.3 14.8 515 23.5 30.6 Dentro V. Pane, P. M. San . Denpick, D.DDemet. A E Erickson, N A Dubai, S.T. Mysim, E Il Mous, and E T. Smith, J. Chm. 2002.79, 1114 210 2.50 343 750 10.00 (a) (8 pts) Prepare a graph(a table grid is provided) to find the concentration of Sr in the 10-ml sample solution in parts per billion-ng/ml (b) (4 pts) Find the concentration of Sr in tooth enamel in parts per million Ⓡug/g.

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Answer 1

stondaad addihon method. by adde d a) This is a concentsatfon a. S* veasus nal 1+gives a stoaight ihe magnitude ntescept is the concentsation of S and unknow So y 3.136 t2 7.36 40 3D 5 lo I5 CONCENTRATION Of S In above goap, The magnitude otx-hteept is 8,72 : The concentsation s 799m/m 8.72 Ppb b) Nouo let us calculate mass e s in loml 8 72 ngxlom g7.2ng 1 m L mass e sample in tomg is o. 757mg Calculate the concentsahon esr fn toothename 3 10 X Ing 87,9 ng Img X 15 0.757mg Concentaation af sr n tooth eham el s 15 Ppm SIONAL