Lab 3 Redox and Activity Series PDF

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CHEM 161L ...

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Booshkenbobben DeezNutz CHEM 161L TA: Brett Cain 24 September 2018 Lab 3: Redox and Activity Series PART A 1. Based on my observations, the stronger oxidizing agent is chlorine (bleach). When you add the chlorine to the iodine solution, the chlorine oxidizes the negatively charged iodine. Chlorine is being reduced (gaining an electron) 2. a. NaOBr would be able to oxidize I- to iodine (I2) b. Based on my prediction, oxidizing power decreases as you go down the periodic table. c. Our observations and predictions support this trend because chlorine is located higher than iodine in the periodic table. 3. a. I think we were instructed to separate remaining metal from solution before adding the bleach because it would have contaminated the other experiment. The chlorine would react with the zinc instead of trying to oxidize the iodine. The purpose of this experiment was to figure out the stronger oxidizing agent between iodine and chlorine b. If we had not removed the zinc, it would have reacted with the chlorine and formed ZnCl2. PART B

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Chemically, rust forms from iron, water, and oxygen. In this experiment, there was no iron, therefore, the deposit cannot be rust.

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For a rust deposit to form in a solution with only Cu and Al, the aluminum would have to be in the presence of a strong oxidizing solution.

2. a. Oxidizing agent: Cu b. Reducing agent: Al c. Element that was oxidized: Al d. Element that was reduced: Cu PART C 1. a. i.

Ca + 2HCl ➞ CaCl2 + H2

ii. Cu +HCl ➞ CuCl2 + H2 iii. Mg + 2HCl ➞ MgCl2 + H2 iv. Zn + 2HCl ➞ ZnCl2 + H2 v. Sn + 4HCl ➞ SnCl4 + 2H2 vi. Fe + 2HCL ➞ FeCl2 + H2 vii. Ca + 2H2O ➞ Ca(OH)2 + H2 b. The electronegativity trend on the periodic scale can help determine the reactivity of an element. Electronegativity decreases as you go diagonally down and left on the periodic

table. From our observations with experimenting with metals, a decrease in electronegativity leads to more reactivity. Decreased electronegativity in metals means it is easier to lose electrons and becomes more reactive because it uses less energy to get a full outer shell. Magnesium and calcium were the most reactive with HCl and their placement on the periodic table supports this. PART D 1. a. Strongest reductant: Ca b. Weakest reductant: Sn c. Rank (strongest to weakest) i.

Ca

ii. Zn iii. Mg iv. Fe v. Cu vi. Sn As stated in PART C, electronegativity determines reactivity in metals. For example, Ca (strongest reductant) is placed on the periodic table with the lowest electronegativity out of the selected metals because it is lower than Mg and much farther left than Fe, Cu, Zn, and Sn....