What is the oxidation number of chromium in the ionic compound ammonium dichromate, (NH4)2Cr₂O7? a. +3 d. +6 b. +4 e. +7 C. +5 What is the oxidation number of carbon in the ionic compound potassium carbonate, K₂CO3? +6 +7 a. +3 b. +4 C. +5 d. e.

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?

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.

One of the few industrial-scale processes that produce organic compounds electrochemically is used by the Monsanto Company to produce1,4-dicyanobutane. The reduction reaction is 2CH2CHCH+2H++2eNC(CH2)4CN The NC(CH2)4CN is then chemically reduced using hydrogen gas to H2N(CH2)6NH2, which is used in the production of nylon. What current must be used to produce 150.kg NC(CH2)4CN per hour?

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

Gold can be dissolved from gold-bearing rock by treating the rock with sodium cyanide in the presence of oxygen. 4 Au(s) + 8 NaCN(aq) + O2(g) + 2 H2O() 4 NaAu(CN)2(aq) + 4 NaOH(aq) (a) Name the oxidizing and reducing agents in this reaction. What has been oxidized, and what has been reduced? (b) If you have exactly one metric ton (1 metric ton = 1000 kg) of gold-bearing rock, what volume of 0.075 M NaCN, in liters, do you need to extract the gold if the rock is 0.019% gold?

Magnesium metal (a component of alloys used in aircraft and a reducing agent used in the production of uranium, titanium, and other active metals) is isolated from sea water by the following sequence of reactions: Mg2+(aq)+Ca(OH)2(aq)Mg(OH)2(s)+Ca2+(aq)Mg(OH)2(s)+2HCl(aq)MgCl2(s)+2H2O(l)MgCl2(l)electrolysisMg(s)+Cl2+Cl2(g) Sea water has a density of 1.026 g/cm3 and contains 1272 parts per million of magnesium a5 Mg2+(aq) by mass. What mass, in kilograms, of Ca(OH)2; is required to precipitate 99.9% of the magnesium in 1.00103 L of sea water?

One method for determining the purity of aspirin (C9H8O4) is to hydrolyze it with NaOH solution and then to titrate the remaining NaOH. The reaction of aspirin with NaOH is as follows: A sample of aspirin with a mass of 1.427 g was boiled in 50.00 mL of 0.500 M NaOH. After the solution was cooled, it took 31.92 mL of 0.289 M HCl to titrate the excess NaOH. Calculate the purity of the aspirin. What indicator should be used for this titration? Why?