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The biuret tests for
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Proteins (by reacting to peptide bonds)
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What is the natural color of the Biuret reagent?
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Blue
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What color signifies a strong positive reaction for proteins in the Biuret test
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Violet
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When trying to identify the color (result) of the Biuret test what is recomended?
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Hold the solution up against a white background to read the colors more accurately.
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What is a peptide bond?
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The covalent bond between two amino acid units, formed by a dehydration reaction.
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Name some substances that test positively for proteins in the biuret test
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Egg albumin, milk, hamburger juice, gelatin,
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Name some substances that test negatively for proteins in the biuret test
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Water, amino acid
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After being shaken vigorously, how long must the biuret test sit for before reading the results?
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3 min.
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What does the Silver nitrate test, test for?
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Salts, (halide ions such as chloride, bromide and iodide)
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Sodium chloried makes up_________
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Sea Salt
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What happens when a few drops of silver nitrate is added to water
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It immediately produces a milky white precipitate which will be intense and persistent if the solution has a significant concentration of chloride ions.
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Salt is found by___________
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Searching for Chloride ions
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What does a pale cream or yellow precipitate indicate in the silver nitrate test
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Bromide or iodide ions
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What samples had white precipitate in the silver nitrate test
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Salt solution, salad dressing,
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What samples did not produce white precipitate in the silver nitrate test
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Water, meat juice, starch
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