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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
Introductory Chemistry: A Foundation
- 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_forwardOne 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?arrow_forward
- Write 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_forwardWrite balanced chemical equations for the following reactions. (a) The reaction of aluminum and iron(III) oxide to form iron and aluminum oxide (known as the thermite reaction). (b) The reaction of carbon and water at high temperature to form a mixture of gaseous CO and H2 (known as water gas and once used as a fuel). (c) The reaction of liquid silicon tetrachloride and magnesium forming silicon and magnesium chloride. This is one step in the preparation of ultrapure silicon used in the semiconductor industryarrow_forwardAluminum 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_forward
- What 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_forwardThe balanced equation for the reduction of iron ore to the metal using CO is Fe2O3(s) + 3 CO(g) 2 Fe(s) + 3 CO2(g) (a) What is the maximum mass of iron, in grams, that can be obtained from 454 g (1.00 lb) of iron(III) oxide? (b) What mass of CO is required to react with 454 g cot Fe2O3?arrow_forward
- Balance the following equations: (a) for the reaction to produce "superphosphate" fertilizer Ca3(PO4)2(s) + H2SO4(aq) Ca(H2PO4)2(aq) + CaSO4(s) (b) for the reaction to produce diborane, B2H6 NaBH4(s) + H2SO4(aq) B2H6(g) + H2(g) + Na2SO4(aq) (c) for the reaction to produce tungsten metal from tungsten(VI) oxide WO3(s) + H2(g) W(s) + H2O() (d) for the decomposition of ammonium dichromate (NH4)2Cr2O7(s) N2(g) + H2O() + Cr2O3(s)arrow_forwardIron oxide ores, commonly a mixture of FeO and Fe2O3, are given the general formula Fe3O4. They yield elemental iron when heated to a very high temperature with either carbon monoxide or elemental hydrogen. Balance the following equations for these processes: Fe3O4(s)+H2(g)Fe(s)+H2O(g)Fe3O4(s)+CO(g)Fe(s)+CO2(g)arrow_forwardBromine 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_forward
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