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Prelab Quiz Answers Reproduce the diagram of the well plate shown and label it as you plan to use it. Interpretation of the experiment is 1 simplified if the known solutions are arranged in the order found in Data Table 4.1 Ammonium Ammonium Phosphate Carbonate Boric Acid Aluminum Chloride Acetate Sodium Sodium Sulfate Yamada Litmus Yamada Litmus Carbon Dioxide Distilled Water Unknown C Unknown D Unknown A Unknown B in Water A correlation between pH of a solution and its color in the presence of Yamada's Universal indicator is given in the 2 procedure section of the lab. What color would you expect a strongly basic solution? Dark Blue or Violet 3 What is the purpose in Part II of the experiment, in which the known solutions are spotted on DY4 paper? To determine if DY4 is an acid or base indicator 4 Why, after dying the multi-fiber strip, is it rinsed first with distilled water and then with tap water? To determine which fabrics are dyed by the DY4 paper (which materials the indicator will bind to) and then to determine which fabrics, once bound or dyed, are pH sensitive Lab 5 Answers Yamada Acid/Base/ Color on DY4 Litmus pH Solution Color Neutral Paper 0.1M Al2SO4 Red Pink Acid 2 0.1M Al2SO4 Clear 2M NH4Cl Orange Violet Acid 4 2M NH4Cl Clear 0.3M Boric Acid Yellow Violet Acid 6 0.3M Boric Acid Clear 1M NH4Ac Green Violet Neutral 7-8 1M NH4Ac Orange 0.2M Na3PO4 Blue Blue Base 9 0.2M Na3PO4 Red 0.2M Na2CO3 Violet Blue Base 10-11 0.2M Na2CO3 Dark Red Dry Ice (CO2) Red Pink Acid 2-3 pH at which DY4 Distilled Water changes Green Violet Neutral 7 7-8 Unknown A Red Pink Acid 2-3 Unknown B Violet Blue Base 10 Fiber Color Fast pH Sensitive Unknown C Green Violet Base 7-8 Acetate Unknown D Yellow Violet Acid 5-6 Self-Extinguishing Fiber Questions: Arnel Bleached Cotton Yes Yes 1 What universal indicator colors are associated with acid solutions? Creslan 61 Red, Orange, Yellow Dacron 54 2 What universal indicator colors are associated with base solutions? Dacron 64 Nylon 66 Yes Orlon 75 Dark Green, Blue, Violet Spun Silk Yes 3 What universal indicator colors are associated with neutral solutions? Polypropylene Rayon Yes Yes Green or Light Green Wool Yes 4 Recall that the philosophical origins of acids and bases may be traced to the warring opposites philosophy of Empedocles; such a philosophy tends to emphasize extremes (good vs. evil, black vs white). Litmust is a two color indicator whereas universal indicator is a multicolor acid base indicator. This multicolor behavior of the universal indicator represents a chemical reality and not a chemical philosophy. Do the results suggest that there are only two extreme measurements: acid or base? No, various different levels of pH indicate various strengths of acid and base. In addition, there is also neutral, which is neither acid nor base.
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