اکسل 58228 /
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کد پروژه: 418670
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#کد_پروژه: 58228
موضوع: پروژه اکسل /
A1) The following results were obtained when each of a series of standard silver solutions was analysed by flame atomic-absorption spectrometry.
A: Determine the slope and intercept of the calibration plot, and their confidence limits (CL:95%).
B: Estimate the confidence limits for the silver concentrations in (a) a sample giving an absorbance of 0.456 in a single determination, and (b) a sample giving absorbance values of 0.308, 0.314, 0.347 and 0.312 in four separate analyses.
C: Estimate the limit of detection and limit of quantitation of the silver analysis from the data.
A2) Tooth enamel consists mainly of the mineral calcium hydroxyapatite, Ca10(PO4)6(OH)2. Trace elements in teeth of archeological specimens provide anthropologists with clues about diet and diseases of ancient people. Students at Hamline University used atomic absorption spectroscopy to measure strontium in enamel from extracted wisdom teeth. Solutions were prepared with a constant total volume of 10.0 mL containing 0.750 mg of dissolved tooth enamel plus variable concentrations of added Sr.
(a) Find the concentration of Sr and its uncertainty in the 10-mL sample solution in parts per billion 5 ng/mL.
(b) Find the concentration of Sr in tooth enamel in parts per million 5 mg/g.
(c) If the standard addition intercept is the major source of uncertainty,find the uncertainty in the concentration of Sr in tooth enamel in parts per million.
(d) Find the 95% confi dence interval for Sr in tooth enamel.
A3) The CdSe content (g/L) of six different samples of nanocrystals was measured by two methods. Do the two methods differ signifi cantly at the 95% confidence level? نمودار اکسل
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