Tag Archives: concentrations

Analysis of Pb in Biological and Environmental Samples

A paper by Yan, et. al. [Yan, X.-P.; Sperling, M.; Welz, B. Anal. Chem. 1999, 71, 4216-4222] describes a newly developed analytical method for the analysis of biological and environmental samples containing Pb2+ in the presence of a variety of … Continue reading

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Determination of Fat in a Snickers’ Bar

In a recent paper [J. Chem. Educ. 1997, 74, 1108-1111], Snow, Dunn and Patel describe the experimental determination of fat in a SnickersTM candy bar.  The fat was removed by extraction with supercritical CO2, with the sample weighed before and … Continue reading

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In determining the concentration of HCl by titrating against the primary weak base TRIS, the molarity of HCL is calculated using the following equation where GFW is the gram formula weight of TRIS, which is 121.136 g/mol. (a) Calculate the … Continue reading

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Preparing Solutions

During lab you need to prepare a solution that is 5.00 x 10-2 M Fe(CN)63- using K3Fe(CN)6. (a) Explain how to make 500 mL of this solution so that you know its concentration exactly. (b) If you transfer 5.00 mL … Continue reading

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Concentration of Parathion Solutions

Parathion, C10H16NO5PS, is a toxic organophosphorous pesticide.  A recently published method [Sacks, et al. Anal. Chem. 2000, 72, 2055-2058] for parathion reports a detection limit of 10 ng/mL.  Express this concentration in ppm and molarity.

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Concentrations

Gratzel et. al. [Anal. Chem. 1999, 71, 2751-2756] describe the use of a diffusional microburet to transfer solutions to very small droplets of solvent. The purpose of their work is to run conventional analyses, such as titrations, on an extremely … Continue reading

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