3. In each of these reactions assign oxidation numbers to all species, and tell which substance is oxidized and which is reduced. Tell which is the oxidizing agent and which is the reducing agent. 2 Al(s) + 3 Cl2(g)  -> 2 AlCl3(s) 8 H3O+(aq) + MnO4-(aq) + 5 Fe2+(aq) -> 5 Fe3+(aq) + Mn2+(aq) + 12 H2O (I) FeS(s) + 3 NO-3(aq) +4 H3O+(aq) -> 3 NO(g) + SO42-(aq) + Fe3+(aq) + 6 H2O (l)

The iron content of hemoglobin is determined by destroying the hemoglobin molecule and producing small water-soluble ions and molecules. The iron in the aqueous solution is reduced to iron(II) ion and then titrated against potassium permanganate. In the titration, iron(ll) is oxidized to iron(III) and permanganate is reduced to manganese(II) ion. A 5.00-g sample of hemoglobin requires 32.3 mL of a 0.002100 M solution of potassium permanganate. The reaction with permanganate ion is MnO4(aq)+8H+(aq)+5Fe2+(aq)Mn2+(aq)+5Fe3+(aq)+4H2O What is the mass percent of iron in hemoglobin?

(a) Rank the following metals in their ability to function as reducing agents: Hg, Sn, and Pb. (b) Which halogens will oxidize mercury to mercury(II)?

1. Sometimes a reaction can fall in more than one category. Into what category (or categories) does the reaction of Ba(OH)2(aq) + H+PO4(aq) fit? acid-base and oxidation-reduction oxidation-reduction acid-base and precipitation precipitation

Consider these half-reactions: (a) Which is the weakest oxidizing agent? (b) Which is the strongest oxidizing agent? (c) Which is the strongest reducing agent? (d) Which is the weakest reducing agent? (e) Will Sn(s) reduce Ag+(aq) to Ag(s)? (f) Will Hg() reduce Sn2+(aq) to Sn(s)? (g) Name the ions that can be reduced by Sn(s). (h) Which metals can be oxidized by Ag+(aq)?

An electrolytic cell is set up with Cd(s) in Cd(NO3)2(aq) and Zn(s) in Zn(NO3)2(aq). Initially both electrodesweigh 5.00 g. After running the cell for several hours theelectrode in the left compartment weighs 4.75 g. (a) Which electrode is in the left compartment? (b) Does the mass of the electrode in the right compartmentincrease, decrease, or stay the same? If the masschanges, what is the new mass? (c) Does the volume of the electrode in the right compartment increase, decrease, or stay the same? If the volumechanges, what is the new volume? (The density of Cd is8.65 g/cm3.)

Balance each of the following equations, and classify them as precipitation, acid-base, gas-forming, or oxidation-reduction reactions. Show states for reactants and products (s, , g, aq). (a) CuCl2 + H2S CuS + HCl (b) H3PO4 + KOH H2O + K3PO4 (c) Ca +HBr H2 + CaBr2 (d) MgC12 + NaOH Mg(OH)2 + NaCl

Triiodide ions are generated in solution by the following (unbalanced) reaction in acidic solution: IO3(aq) + I(aq) I3(aq) Triiodide ion concentration is determined by titration with a sodium thiosulfate (Na2S2O3) solution. The products are iodide ion and tetrathionate ion (S4O6). a. Balance the equation for the reaction of IO3 with I ions. b. A sample of 0.6013 g of potassium iodate was dissolved in water. Hydrochloric acid and solid potassium iodide were then added. What is the minimum mass of solid KI and the minimum volume of 3.00 M HQ required to convert all of the IO3 ions to I ions? c. Write and balance the equation for the reaction of S2O32 with I3 in acidic solution. d. A 25.00-mL sample of a 0.0100 M solution of KIO. is reacted with an excess of KI. It requires 32.04 mL of Na2S2O3 solution to titrate the I3 ions present. What is the molarity of the Na2S2O3 solution? e. How would you prepare 500.0 mL of the KIO3 solution in part d using solid KIO3?

Balance each of the following oxidationreduction reactions by using the oxidation states method. a. C2H6(g) + O2(g) CO2(g) + H2O(g) b. Mg(s) + HCl(aq) Mg2+(aq) + Cl(aq) + H2(g) c. Co3+ (aq) + Ni(s) Co2+(aq) + Ni2+(aq) d. Zn(s) + H2SO4(aq) ZnSO4(aq) + H2(g)

The amount of oxygen, O2, dissolved in a water sample at 25 C can be determined by titration. The first step is to add solutions of MnSO4 and NaOH to the water to convert the dissolved oxygen to MnO2. A solution of H2SO4 and KI is then added to convert the MnO2 to Mn2+, and the iodide ion is converted to I2. The I2 is then titrated with standardized Na2S2O3. (a) Balance the equation for the reaction of Mn2+ ions with O2 in basic solution. (b) Balance the equation for the reaction of MnO2 with I in acid solution. (c) Balance the equation for the reaction of S2O32 with I2. (d) Calculate the amount of O2 in 25.0 mL of water if the titration requires 2.45 mL of 0.0112 M Na2S2O3 solution.