Determine the oxidation states of the elements in the following compounds: (a) Nal (b) GdCl3 (c) LiNO3 (d) H2Se (e) Mg2Si (f) RbO2, rubidium superoxide (g) HF

Four metals, A, B, C, and D, exhibit the following properties: (a) Only A and C react with 1.0 M hydrochloric acid to give H2(g). (b) When C is added to solutions of the ions of the other metals, metallic B, D, and A are formed. (c) Metal D reduces Bn+ to give metallic B and Dn+. Based on this information, arrange the four metals in order of increasing ability to act as reducing agents.

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?

The Toliens test for the presence of reducing sugars (say, in a urine sample) involves treating the sample with silver ions in aqueous ammonia. The result is the formation of a silver mirror within the reaction vessel if a reducing sugar is present. Using glucose, C6H12O6, to illustrate this test, the oxidation-reduction reaction occurring is C6H12O6 (aq) + 2 Ag+(aq) + 2OH(aq) C6H12O7(aq) + 2 Ag(s) + H2O() What has been oxidized, and what has been reduced? What is the oxidizing agent, and what is the reducing agent? Tolien's test. The reaction of silver ions with a sugar such as glucose produces metallic silver. (a) The set-up for the reaction. (b) The silvered test tube

Bromine is obtained from sea water by the following redox reaction: Cl2(g) + 2 NaBr(aq) 2 NaCl(aq) + Br2() (a) What has been oxidized? What has been reduced? (b) Identify the oxidizing and reducing agents.

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)

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

Determine the oxidation number of each element in each of the following compounds: (a) HCN (b) OF2 (c) ASCl3

Chromium has been investigated as a coating for steel cans. The thickness of the chromium film is determined by dissolving a sample of a can in acid and oxidizing the resulting Cr3+ to Cr2O72 with the peroxydisulfate ion: S2O82(aq) + Cr3+(aq) + H2O(l) Cr2O72(aq) + SO42(aq) + H+(aq) (Unbalanced) After removal of unreacted S2O82 an excess of ferrous ammonium sulfate [Fe(NH4)2(SO4)26H2O] is added, reacting with Cr2O72 produced from the first reaction. The unreacted Fe2+ from the excess ferrous ammonium sulfate is titrated with a separate K2Cr2O7 solution. The reaction is: H+(aq) + Fe2+(aq) + Cr2O72(aq) Fe3+(aq) + Cr3+(aq) + H2O(l) (Unbalanced) a. Write balanced chemical equations for the two reactions. b. In one analysis, a 40.0-cm2 sample of a chromium-plated can was treated according to this procedure. After dissolution and removal of excess S2O82, 3.000 g of Fe(NH4)2(SO4)26H2O was added. It took 8.58 mL of 0.0520 M K2Cr2O7 solution to completely react with the excess Fe2+. Calculate the thickness of the chromium film on the can. (The density of chromium is 7.19 g/cm3)