The Chemistry of Natural Waters sf.docx - The Chemistry of...

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The Chemistry of Natural WatersSamantha Felice10/17/2019TA: Gabby DiDomizioGroup Members: Damian Farris,Sam Earl,Abby DruffnerIntroduction:
All water contains some level of hardness to it, whether it is from bottles, the tap, creeks, rivers,or the rain. Hardness of water is best defined as the amount of molecules of cations are in thewater. This usually pertains to the Calcium and Magnesium ions are in the water, although othermolecules contribute towards the hardness of the water as well. The greater the content of2+¿Mg¿and2+¿Ca¿, the more “hard,” or molecule dense the water is.Atomic Absorption Spectrometry, AAS, is a method of detecting the amount of Magnesium, andCalcium in liquid substances through determining the wavelength of electromagnetic radiationwhen using a monochromatic light. The light projects through the substance, and atoms that haveelectronic energy separation (Δ E), and absorb light. Both elements absorb the wavelengthsdifferently, so that’s why there is two separate AAS machines used in this experiment fordetection of Calcium and detection of Magnesium ions. Region 1 of the AAS chamber contains alam and (HCl’s). Region 1 emits a monochromatic light (Δ E) where the2+¿Mg¿and2+¿Ca¿lamps will determine the amount of2+¿Mg¿and2+¿Ca¿ions are in the sample. Region 2 ofAtomic Absorption Spectrometry has the sample chamber and burner. The sample is sucked in,and then aspirated into the sample chamber, where it is converted to aerosol. This therefore is putinto the burner, which then atomizes the sample. Light passes through the aerosol and themolecules are absorbed if there is EE matching energy present. Region 3 chamber contains themonochromator detector. The grating is adjusted towards the wavelength, which corresponds toΔ Eof the metals that finally falls to the photomultiplier tube, PMT. The metal atoms absorbsome light passing through the flame from the lamp, so a decrease in the initial signal is detected2
by the PMT. This decrease is directly proportional to the concentration of the metal in thesample. Finally, the amount of the metal in the sample solution is determined through creating acalibration graph. The accuracy of the instrument used is determined through the CheckStandards of the calibration graph, which is the concentration of the metal ion in comparison tothe correct values.The primary goal of Experiment 10 is to analyze the water in order to determine the hardness ofit. Figure 1 below shows the schematic of how the AAS instrument works.Figure 1.EDTA will be used to titrate with the standard solution made from calcium carbonate, CaCO3.The EDTA solution can then be used to determine the hardness of an unknown water sample.Since both EDTA and Ca2+ are colorless, it is necessary to use a special indicator to detect theend point of the titration. As EDTA is added, it will complex free Ca2+ and Mg2+ ions, leavingthe MgIn– complex alone until essentially all of the calcium and magnesium have beenconverted to chelates. At this point EDTA concentration will increase sufficiently to displace3

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Term
Fall
Professor
NoProfessor
Tags
Drinking water, State college

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