Lab_8-S08-vitamins - Lab 8 Vitamin Examination Laboratory...

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Lab 8: Vitamin Examination Laboratory Goals In this lab you will: Learn how to test for cations and anions in a solution Use the inorganic material tests to analyze a multi-vitamin Safety Notes You will be working with concentrated acids and bases, NaOH pellets, and other potentially harmful materials. Keep in mind that acids and bases of this strength can cause permanent damage (especially to eyes.) WEAR SAFETY GOGGLES AT ALL TIMES! You will also be using Bunsen burners. BE CAREFUL! Introduction In the past we have done a quantitative analysis where we found out how much of a substance is present in a sample. In this lab you will be performing a qualitative analysis on a vitamin. This process allows you to determine what is present in a sample. Most of the tests in this lab will utilize the solubility rules to determine the presence of anions or cations. Other tests will require adding a chemical to shift the equilibria as explained by LeChâtelier’s Principle. For each of these tests you will use known compounds to determine what each a positive and negative test looks like prior to performing the same tests on your vitamin sample. There are two parts to this lab. You should work in pairs, though try to work with someone with whom you have not previously worked. In Part One you will be testing two solutions (A and B) and distilled water. Solution A will contain the cations Ca +2 , Na + , Fe +3 , NH 4 + , and Zn +2 . Solution B will contain the anions Cl - , I - , PO 4 -3 , and SO 4 -2 . The solutions will show you what positive tests look like. The distilled water will show you what negative tests look like. In Part Two you will prepare and analyze the multi-vitamin sample. In this laboratory you will be using the centrifuges to quickly separate suspensions. Whenever you are using a centrifuge it is critical that you counterbalance the machine. This means that in addition to your test tube of material that you are trying to separate, it is critical that you insert a second test tube of equal weight to the one you are trying to separate (i.e. containing the same amount of liquid) in the hole directly opposite your sample tube before spinning. If the weight of the two tubes is not close, there is a good chance that one or both of the two tubes will break and in addition to preventing anyone else from using the machine, you will get the joy of cleaning up the broken glass and spilled chemicals. For this reason, the lid must also be closed anytime the centrifuge is in use. Keep in mind that NOT turning the centrifuge to the maximum speed will significantly reduce the likelihood of catastrophic misbalancing. 8-1
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Prelab Assignment View the windows media file which discuss analysis of the chloride and iodide ions. Prelab2_media.wmv
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Lab_8-S08-vitamins - Lab 8 Vitamin Examination Laboratory...

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