Experiment 10 Final Lab.docx - 1 Experiment 10 Natural...

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1 Experiment 10: Natural Waters Section A. Determination of Water Hardness by Atomic Absorption Spectroscopy (AA) Section B. Evaporation of Your Water Sample to Give Total Dissolved Solids Complete before lab. Goal: To investigate and analyze water hardness within a sample through a wide variety of removal methods Procedure: Thompson, S. PSU Chemtrek: Expt 10: Natural Waters; Keiser, J., Hayden-McNeil Publishing: Plymouth, MI, 2020, pp 19-1 – 19-22. Complete before lab. Read through this section in your Chemtrek and watch the associated video. Follow up with your TA with any questions. Briefly summarize this section. To obtain the data for your specific sample, consult the Experiment 10 Data Table linked in the Experiment 10 module on Canvas. During this section, we will be using Atomic Absorption (AA) spectroscopy to determine the hardness within our sample. I will be testing creek water from Walnut Springs Park. Since, the given sample had a very high hardness reading initially, a 5ml sample was taken along with 5ml of distilled water to bring the sample to a readable dilution factor of 2. 2 blub measured samples of Walnut Springs and place them within a 24-well tray to be used as a well holder for your samples. Once this is completed calibrate with the aspirator tube of the AA machine with distilled water. Next, measure the first sample for calcium absorbance. Finally, measure the next sample for you averaged magnesium absorbance. Complete before lab. Read through this section in your Chemtrek and watch the associated video. Follow up with your TA with any questions. Briefly summarize this section. To obtain the data for your specific sample, access the folder of TDS images linked in the Experiment 10 module on Canvas. During this section, we will be making a qualitative measurement of the Total Dissolved Salts (TDS) of the Walnut Springs Sample. This measurement is related to hardness but includes all salts that are dissolved within a given sample. To begin, obtain a small amount of aluminum foil and place it shiny side up with some tweezers on a hot plate of low to medium heat. On this aluminum foil place 1 drop of undiluted sample, 1 drop of distilled water .5 cm away, and a drop of .001 M Ca 2+ another .5 com away from the other 2 drops. Allow the water to evaporate and once the process is complete remove the foil from the plate with a pair of tweezers. What is left behind will be the non-volatile salts that were present within each sample.

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