Explore BrainMass

Explore BrainMass

    Oxidation-Reduction and Electrochemistry

    Redox Reactions, Oxidation Numbers, Limiting Reagent and Yield Problems

    1. One of the steps in the commercial process of converting ammonia to nitric acid is the conversion of NH3 into NO: 4NH3(g) + 5O2(g) ---> 4NO(g) + 6H2O(g) In a certain experiment, 2.25 g of NH3 reacts with 3.75 g of O2. a) Which is the limiting reactant? b) How many grams of NO form? c) How many grams of the excess react

    Dilution, Titration and Redox Problems

    1. Draw me a beaker for each of the following 3 solutions. Show (label) the particles that exist when 1 particle of each dissolves. You don't have to show the water molecules! H3P04 C12H22011 HCHOO 2. Balance the following redox reaction that occurs in basic solution. NO2- (aq) + Al (s) ---> NH3 (g) + Al02- (aq) 3. Descr

    oxidation number of the atoms

    Determine the oxidation number for the indicated element in each of the following substances. S in SO2 C in COCl2 Mn in MnO4- Br in HBrO As in As4 O in K2O2 Im pretty lost on how to find them.

    Electrode Potential and Gibbs Free Energy Problems

    1. What is the standard electrode potential for the half reaction in which free ferric ion is reduced to elemental Iron? 2. Place the following chemical species in ascending order (in energetic terms) as electron acceptors under standard conditions. Fe3+ (reduced to Fe2+); Zn2+ (reduced to Zn); H+;Ag+;Cu2+ (reduced to Cu+)

    Reaction Products from Aldehydes and Alcohols in Atmosphere

    In air pollution chemistry and control, how is it that many common organic air pollutants such as methanol, formaldehyde, acetaldehyde, and phenol lose their oxygen ions and get converted ultimately to CO2 and H2O. For instance: CH3OH --> CH4 CH2O --> CO2 + H2O CH3CHO --> C2H4 C6H5OH --> C6H6 In each of these cases, wh

    the weakest reducing agent

    What criteria do you use to determine that an ion is the weakest reducing agent among several substances? Examine the following half-reactions and select the weakest reducing agent among the substances: Cr(OH)3(s) + 3e- <--> Cr(s) + 3OH-(aq) E= -1.48V SnO2(s) + 2H20(l) + 4e- <--> Sn(s) + 4OH

    oxalate concentration for calcium oxalate to precipitate

    7. The Ksp for calcium oxalate (CaC2O4) is 2.7 x 109. If the free Ca+2 concentration were 1mM, what would need to be the oxalate concentration for calcium oxalate to precipitate? 8. What would be the voltage of a Zn|Zn+2||Cu+2|Cu cell, once the concentration of Zn+2 went to 1.5M and the CU+2 concentration diminished to 0.5M?

    Voltage for a Standard Cell

    Using the electrode potentials in appendix C3 of your text, calculate the voltage for a standard cell using the following reaction: H2O2 + MnO2 + H+ &#8594; Mn+2 + O2 + H2O

    Redox Reactions: Oxidation and Reduction

    Can you please check this one: MnO4- + HSO3- (in acidic solution) Oxidation: MnO4- + 5e- + 8 H+ --> Mn2+ + 4 H2O Reduction: HSO3- + H2O --> SO42- + 2 e- + 3 H+ Balanced Equation: 2 MnO4- + 5 HSO3- + H+ --> 2 Mn2+ + 5 SO42- + 3 H2O I am having difficulty with these (especially, the ones in solution) Cyclohexanol + HO

    IR Spectroscopy Puzzle

    Explain how the information from the IR spectrum will be used to solve this puzzle. There are 2 puzzles; answer that question for each of them. See attached file for full problem description.

    Haloform Reactions

    The haloform reaction using I2 and NaOH is referred to as the "iodoform" test for methyl ketones. The test also gives positive results for compounds containing the -CH(OH)CH3 group. This results from the oxidation of the alcohol to the methyl ketone in the first stage. Write a balanced equation for the conversion of C6H5CHOHCH3

    Oxidation states of Chromium

    Chromium is a metal with many oxidation states, which of the following compounds has chromium in its lowest oxidation state? Cr2O3 Cr2O7^2- MgCr2O3

    Quantitative Analysis of Metallic Iron

    I put the penny in the silver nitrate solution for a half hour. The penny gives black precipitation and bubbles which come off the surface of the penny. My questions: 1. What is the gas that comes off the surface of the penny? (Hint: the half reactions that are going on between silver ions and copper) 2. Which is being red

    The Nernst Equation in Electrochemistry

    (See attached file for full problem description) --- The Nernst equation is the most important equation in electrochemistry. It is defined as follows: Where is the standard reduction potential of the reaction is the gas constant is the temperature (in Kelvin) is the number of moles of electrons transferred in

    Assigning Oxidation Numbers

    I need some aid in assigning oxidation numbers to each element in the following equations and identify the oxidizing and reducing agents: CuO(s) + H2(g) ? Cu(s) + H2O(g)

    Oxidation or Reduction

    I need some help indicating whether this chemical reaction is an oxidation, reduction or neither: Ag (superscript +) (aq) + Cl (aq)-->AgCl(s)

    Cell Potential and Reduction Potentials

    Hi. Can someone please explain to me how to do the following question? I'm quite confused about how to do these. See attachment for better notation representation. Consider the following reaction at 25 degrees C, [Al3+] = 2.0 M and [Zn2+] = 1.0M 2 Al (s) + 3 Zn2+ (aq) -> 3 Zn (s) + 2 Al3+ (aq) a) Predict if the cell po

    Exchange Current Density of Metal Ions

    The following data were obtained for the reduction of metal ions A+ to metal A in a stirred solution at a 0.1 cm^2 electrode; the solution contained 0.01M A+. n(mV) -100 -120,-150, -180, -220, -280, -370, -500, -600 i(uA) -45.9, -62.6, -100, -170, -300, -510, -770, -965, -965 Calculate the exchange current density jo[uA/

    Mendeleev and the periodic table

    1. Why did Mendeleev leave three blank spaces in his periodic table? 2. Why do elements in a group of the periodic table have similar properties? 3. List five different metals give examples of how each metal is used. 4. List five different nonmetals. Give examples of how each nonmetal is used. 5. Why would you expect to find

    Products of Alcohol Oxidation

    What kind of product might result from the oxidation of the following (ethanol, 2-propanol, 2-methyl-2-propanol) an aldehyde or a ketone? Which reactions might occur with difficulty? Which reactions might not occur at all? What would each of their temperatures, color, odor, and reaction rates be? NOTE: In the

    Grignard reagent and synthesis of compounds

    3. A novice chemist wishes to prepare 1-methyl-1,4-cyclohexanediol from the compound shown below (see attached). He wishes to use an appropriate Grignard reagent in the synthesis. Was the chemist successful? Explain why or why not. 4. Synthesize the following compounds using the indicated starting materials. a) Show TWO wa

    Oxidation States of Iron and Color Differences

    Both normal oxidation states of iron, Fe, will form low spin complex ions with cyanide (CN-); i.e., [Fe(CN)6]4 minus (aq) and [Fe(CN)6] 3 minus(aq). However the color of these ions is not the same. One ion is green-yellow (more yellow than green), which means it absorbs violet to blue light and the other is blood red in color,

    Identify the unknown compounds

    An unknown is either 2-methyl-2-propanol or 2 methyl-1-propanol. Addition of a few drops of dichromate solutions (orange as a strong oxidizing agent) to the unknown results in a green solutions (the color after it has been reduced). What is the identity of the unknown? Explain.

    Oxidation of Limonene

    Limonene, C10H16, a terpene found in citrus peel, absorbs only two moles of hydrogen forming p-menthane C10H20. Oxidation by permanganate converts limonene into structure A in the attached .jpg (ignore structures B and C for this problem). 1. How many rings, if any, are in limonene? 2. What structures are consistent wit

    pH at 25 degrees Celsius

    A hydrogen electrode (PH2 = 1.00 atm), a salt bridge, and a calomel electrode (E=0.280 V) are used to determine the pH of a solution. If the combination (i.e. a solution, the hydrogen electrode and the calomel electrode) gives a voltage of 0.790 V, what is the pH of the solution at 25 degrees Celsius?

    Carbon Disulfide, CS2

    Carbon Disulfide, CS2, is an important industrial substance. Its fumes can burn explosively in air to form sulfer dioxide and carbon dioxide. CF2(g) + O2(g) (arrow) SO2(g) + CO2(g) If 1.60 mol of CS2 burns with 5.60 mol of O2, how many mols of the excess reactant will still be present when the reaction is over.? Also .