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The Hall process is an important method by which pure aluminum is prepared from its oxide (alumina,
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Chapter 6 Solutions
EBK INTRO.CHEMISTRY (NASTA EDITION)
- Three reactions very important to the semiconductor industry are The reduction of silicon dioxide to crude silicon, SiO2(s) + 2 C(s) → Si(s) + 2 CO(g) ΔrH° = 689.9 kJ/mol The formation of silicon tetrachloride from crude silicon, Si(s) + 2 Cl2(g) → SiCl4(g) ΔrH° = −657.01 kJ/mol The reduction of silicon tetrachloride to pure silicon with magnesium, SiCl4(g) + 2 Mg(s) → 2 MgCl2(s) + Si(s) ΔrH° = −625.6 kJ/mol Calculate the overall enthalpy change when 1.00 mol sand, SiO2, changes into very pure silicon by this series of reactions.arrow_forwardThe carbon dioxide exhaled in the breath of astronauts is often removed from the spacecraft by reaction with lithium hydroxide 2LiOH(s)+CO2(g)Li2CO3(s)+H2O(l) Estimate the grams of lithium hydroxide required per astronaut per day. Assume that each astronaut requires 2.50 103 kcal of energy per day. Further assume that this energy can be equated to the heat of combustion of a quantity of glucose, C6H12O6, to CO2(g) and H2O(l). From the amount of glucose required to give 2.50 103 kcal of heat, calculate the amount of CO2 produced and hence the amount of LiOH required. The H for glucose(s) is 1273 kJ/mol.arrow_forwardWrite balanced net ionic equations for the following reactions in acid solution. (a) Liquid hydrazine reacts with an aqueous solution of sodium bromate. Nitrogen gas and bromide ions are formed. (b) Solid phosphorus (P4) reacts with an aqueous solution of nitrate to form nitrogen oxide gas and dihydrogen phosphate (H2PO4-) ions. (c) Aqueous solutions of potassium sulfite and potassium permanganate react. Sulfate and manganese(II) ions are formed.arrow_forward
- Aluminum is produced commercially by the electrolysis of Al2O3 in the presence of a molten salt. If a plant has a continuous capacity of 1.00 million A, what mass of aluminum can be produced in 2.00 h?arrow_forwardWhat is Hrxn for reaction of iron(III) oxide and carbon monoxide to give iron metal and carbon dioxide gas? Use the following reactions: 4Fe(s)+3O2(g)2Fe2O3(s)H=1648.4kJ4CO(g)+O2(g)2CO3(g)H=565.98kJarrow_forwardNitric acid is produced commercially by the Ostwald process, represented by the following equations: 4NH3(g)+5O24NO(g)+6H2O(g)2NO(g)+O2(g)2NO2(g)3NO2(g)+H2O(l)2HNO3(aq)+NO(g) What mass of NH3 must be used to produce 1.0 106 kg HNO3 by the Ostwald process? Assume 100% yield in each reaction, and assume that the NO produced in the third step is not recycled.arrow_forward
- 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.arrow_forwardBalance each of the following equations, and then write the net ionic equation. Show states for all reactants and products (s, . g, aq). (a) the reaction of sodium hydroxide and iron(II) chloride to give iron(II) hydroxide and sodium chloride (b) the reaction of barium chloride with sodium carbonate to give barium carbonate and sodium chloride (c) the reaction of ammonia with phosphoric acidarrow_forwardThe 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?arrow_forward
- 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?arrow_forward4.48 Elemental phosphorous is used in the semiconductor industry. It can be obtained from an ore called fluoroapatite via reaction with SiO2 and C: 4Ca5( PO4)3F+18SiO2+30C3P4+30CO+18CaSiO3+2CaF2 Suppose a particular semiconductor production plant requires 1500 kg of P4. If the recovery of P4 from this reaction is 73% efficient, what mass of fluoroapatite is needed?arrow_forwardEthanol, C2H5OH, is a gasoline additive that can be produced by fermentation of glucose. C6H12O62C2H5OH+2CO2 (a) Calculate the mass (g) of ethanol produced by the fermentation of 1.000 lb glucose. (b) Gasohol is a mixture of 10.00 mL ethanol per 90.00 mL gasoline. Calculate the mass (in g) of glucose required to produce the ethanol in 1.00 gal gasohol. Density of ethanol = 0.785 g/mL. (c) By 2022, the U. S. Energy Independence and Security Act calls for annual production of 3.6 1010 gal of ethanol, no more than 40% of it produced by fermentation of corn. Fermentation of 1 ton (2.2 103 lb) of corn yields approximately 106 gal of ethanol. The average corn yield in the United States is about 2.1 105 lb per 1.0 105 m2. Calculate the acreage (in m2) required to raise corn solely for ethanol production in 2022 in the United States.arrow_forward
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