Solution Manual for Science and Engineering of Materials, SI Edition, 7th Edition

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1Chapter 1: Introduction to Materials Science and Engineering1-1Define materials science and engineering (MSE).Solution:Materials science and engineering (MSE) is an interdisciplinary field that studies andmanipulates the composition and structure of materials across length scales to controlmaterials properties through synthesis and processing.1-2What is the importance of the engineering tetrahedron for materials engineers?Solution:Structure, properties and performance all depend on the route in which a material isprocessed. We cannot predict the end properties for a material until we have specified aprocess to produce the component. Using the same material, but changing the way it isprocessed will result in different structure, properties and performance of that material.This is applicable to all material systems.1-3Define the following terms:(a) composition;(b) structure;(c) synthesis;(d) processing; and(e) microstructure.Solution:(a) The chemical make-up of a material.(b) The arrangement of atoms, seen at different levels of detail.(c) How materials are made from naturally occurring or man-made chemicals.(d) How materials are shaped into useful components.(e) The structure of an object at the microscopic scale.1-4Explain the difference between the terms materials science and materials engineering.Solution:Materials scientists work on understanding underlying relationships between thesynthesis and processing, structure, and properties of materials. Materials engineersfocus on how to translate or transform materials into useful devices or structures.

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21-5The myriad materials in the world primarily fall into four basic categories; what arethey? What are materials called that have one or more different types of materialfabricated into one component? Give one example.Solution:Metals, polymers and ceramics. The addition of one or more of these to a single systemis called a composite. An example of a composite material is fiberglass.1-6What are some of the materials and mechanical properties of metals and alloys?Solution:Metals and alloys have good electrical and thermal conductivity, high strength, ductilityand formability, and high stiffness.1-7What is a ceramic, and what are some of the properties that you expect from a ceramic?Solution:Ceramics tend to have very high compressive strengths, but behave in a brittle (glass-like) manner. They have very high melting temperatures. Poor thermal conductivity andelectrical conductivity make ceramics behave as an insulator instead of a conductor.1-8Make comparisons between thermoplastics and thermosetting polymers (a) on the basisof mechanical characteristics upon heating, and (b) according to possible molecularstructures.Solution:Thermoplastics tend to soften with elevated temperature exposure with graduallydecreasing viscosity. Thermosetting polymers do not soften with elevated temperatureexposure; instead they will remain hard and will degrade, possibly charring withprolonged exposure.Thermoplastics consist of long chain molecular arrangements of covalently bondedcarbon atoms with various side groups. Thermosetting polymers tend to be a complex 3-D arrangement usually deviating from the clearly defined long-chain moleculararrangement.1-9Give three examples of composites that can be fabricated.Solution:Metal matrix composites (MMC) – A metal matrix reinforced with a ceramic material inthe form of particles, whiskers or fibers. Example: Cobalt alloy reinforced with tungsten-carbide particulates.Polymer matrix composites (PMC) – A polymer matrix reinforced with a ceramicmaterial in the form of whiskers or fibers. Example: Kevlar or fiberglass.

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3Ceramic matrix composites (CMC) – A ceramic matrix reinforced with ceramic ormetallic material in the form of whiskers or fibers. Example: Carbon fibers in an alumina(Al2O3) matrix.1-10For each of the following classes of materials, give twospecificexamples that are aregular part of your life:(a) metals;(b) ceramics;(c) polymers; and(d) semiconductors.Specify the object that each material is found in and explain why the material is used ineach specific application.Hint:One example answer for part (a) would be thataluminum is a metal used in the base of some pots and pans for even heat distribution.It is also a lightweight metal that makes it useful in kitchen cookware. Note that in thispartial answer to part (a), a specific metal is described for a specific application.Solution:(a) Aluminum was described in the problem statement. Stainless steel is used forflatware. It is easily formed and has good corrosion resistance, strength, and hardness.(b) Two specific examples of polymers are polystyrene and polytetrafluoroethylene alsoknown as Teflon. Styrofoam is polystyrene rigid foam insulation that is used for cupsthat keep hot drinks warm. Teflon is used as a coating on the inside of kitchen cookwaresuch as frying pans because it prevents food from sticking to the pan while cooking.(c) Two examples of semiconductors are silicon doped with phosphorus (n–type) andsilicon doped with boron (p–type). Both types of impurities convert silicon from a poorinto a useful conductor. Bothnandp–type semiconductors are contained in thesemiconductor device called a diode, so that at the junction between both types,current is able to flow. A diode blocks current in one direction while allowing currentflow in the other direction. A device that uses batteries, e.g. a remote control or acalculator, often contains a diode that protects the device if the batteries are insertedbackward. The diode blocks the current from leaving the battery if it is reversed,protecting the sensitive electronics in the device. Another semiconductor is thecompound semiconductor AlxGa1-xAs, which is used in lasers.(d) Ceramics are compounds that contain metallic and nonmetallic elements. Twospecific examples are tungsten carbide and magnesia. Tungsten carbide is often bondedwith cobalt and/or nickel. Tungsten carbide is used mainly in tips for metal cutting tools(knives can be made with this) because of its good wear resistant characteristics.Magnesia is a heat resistant ceramic that is used in liners for ovens. Magnesia can resisthigh temperatures but is susceptible to thermal stress cracking.

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41-11Describe the enabling materials property of each of the following and why it is so:(a) steel for I-beams in skyscrapers;(b) a cobalt chrome molybdenum alloy for hip implants;(c) polycarbonate for eyeglass lenses; and(d) bronze for artistic castings.Solution:(a) Steel for I-beams in skyscrapers must be strong in order to bear large mechanicalloads.(b) A cobalt chrome molybdenum alloy for hip implants must be biocompatible,meaning that it must not degrade when inserted into the body nor be toxic or otherwisedangerous.(c) Polycarbonate for eyeglass lenses must be transparent and impact-resistant.(d) Bronze can be melted and poured into molds to be shaped. It is also fairly corrosionresistant (which is important for outdoor sculptures). Over long periods of time whensubjected to an outdoor environment, bronze will develop an oxide known as a patina.The patina protects the bronze from further corrosion.1-12Describe the enabling materials property of each of the following and why it is so:(a) aluminum for airplane bodies;(b) polyurethane for teeth aligners (invisible braces);(c) steel for the ball bearings in a bicycle’s wheel hub;(d) polyethylene terephthalate for water bottles; and(e) glass for wine bottles.Solution:(a) Aluminum has a high strength to weight ratio. Thus it has the strength needed towithstand the forces imposed on an airframe, but keeps the weight of the airplane lowcompared to other metals. The lighter the airplane body, the less force it takes to lift theplane into the air. This results in less fuel being used and a reduction in operating costs.Aluminum also has good corrosion resistance.(b) Polyurethane for teeth aligners must be highly formable and transparent. Since teethaligners are worn during the day, a transparent material is desirable to make them lessconspicuous. A unique set of teeth aligners must be produced for each individual, and sothe polyurethane must be easily molded. Computer software is used to producecomputer models of a person’s teeth during various stages of the correction process. Arapid prototyping tool is used to create physical models of the person’s teeth at eachstage. A sheet of polyurethane is then heated and formed onto the models to producethe teeth aligners.

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5(c) Ball bearings in a bicycle’s wheel hub reduce friction between metal surfaces.Therefore, steel is used because it has high strength and hardness.(d) Polyethylene terephthalate is easily formed by a blow molding process and isrecyclable, critical properties for mass-produced water bottles.(e) Glass has high chemical resistance; thus, glass bottles are used to preserve the tasteof the wine contained in them.1-13What properties should an engineer consider for a total knee replacement of adeteriorated knee joint with an artificial prosthesis when selecting the materials for thisapplication?Solution:Properties that should be considered are those relating to strength (fatigue, tensile andcompressive) since the knee sustains static, dynamic and cyclic loads. Hardness willpromote wear resistance. Modulus of elasticity similar to that of the human boneotherwise other problems will occur. Chemical stability in regards to corrosionresistance and cellular toxicity to prevent negative reactions to the material selected.The material needs to have the ability to bond with the residual bone material and havelongevity in order to avoid frequent replacement.1-14Write one paragraph about why single-crystal silicon is currently the material of choicefor microelectronics applications. Write a second paragraph about potential alternativesto single-crystal silicon for solar cell applications. Provide a list of the references orwebsites that you used. You must use at least three references.Solution:Answers will vary.1-15Coiled springs should be very strong and stiff. Silicon nitride (Si3N4) is a strong, stiffmaterial. Would you select this material for a spring? Explain.Solution:Springs are intended to resist high elastic forces, where only the atomic bonds arestretched when the force is applied. The silicon nitride would satisfy this requirement;however, we would like to also have good resistance to impact and at least someductility (in case the spring is overloaded) to ensure that the spring will not failcatastrophically. We also would like to be sure that all springs will perform satisfactorily.Ceramic materials such as silicon nitride have virtually no ductility, poor impactproperties, and often are difficult to manufacture without introducing at least somesmall flaws that cause failure even for relatively low forces. The silicon nitride is NOTrecommended.

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61-16Temperature indicators are sometimes produced from a coiled metal strip that uncoils aspecific amount when the temperature increases. How does this work; from what kindof material would the indicator be made; and what are the important properties thatthe material in the indicator must possess?Solution:Bimetallic materials are produced by bonding two materials having different coefficientsof thermal expansion to one another, forming a laminar composite. When thetemperature changes, one of the materials will expand or contract more than the othermaterial. This difference in expansion or contraction causes the bimetallic material tochange shape; if the original shape is that of a coil, then the device will coil or uncoil,depending on the direction of the temperature change. In order for the material toperform well, the two materials must have very different coefficients of thermalexpansion and should have high enough moduli of elasticity so that no permanentdeformation of the material occurs.1-17What is the purpose of the classification for functional materials?Solution:It specifically categorizes the types of materials used with specific applications. Forinstance, aerospace materials use lightweight materials such as aluminum alloys orcarbon-composites for flight applications instead of using heavy materials such asstainless steel.1-18Explain the difference between crystalline and amorphous materials. Give an example ofeach that you use in your daily life.Solution:Crystalline materials have long-range order arrangement of its atoms while amorphousmaterials have short-range order. One example of a crystalline material is metal and anexample of an amorphous material is glass.1-19If you were given a material and were asked to determine whether it is crystalline oramorphous, how would you determine it?Solution:Crystalline materials can be delineated from amorphous materials using diffractiontechniques. Crystalline materials will produce diffraction patterns while amorphousmaterials will not.1-20List six materials performance problems that may lead to failure of components.Solution:Excessive deformation (overload), fracture, wear, corrosion, fatigue and creep.

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71-21Steel is often coated with a thin layer of zinc if it is to be used outside. Whatcharacteristics do you think the zinc provides to this coated, or galvanized, steel? Whatprecautions should be considered in producing this product? How will the recyclabilityof the product be affected?Solution:The zinc provides corrosion resistance to the iron in two ways. If the iron is completelycoated with zinc, the zinc provides a barrier between the iron and the surroundingenvironment, therefore protecting the underlying iron. If the zinc coating is scratched toexpose the iron, the zinc continues to protect the iron because the zinc corrodespreferentially to the iron (see Chapter 23). To be effective, the zinc should bond well tothe iron so that it does not permit reactions to occur at the interface with the iron andso that the zinc remains intact during any forming of the galvanized material. When thematerial is recycled, the zinc will be lost by oxidation and vaporization, often producinga “zinc dust” that may pose an environmental hazard. Special equipment may berequired to collect and either recycle or dispose of the zinc dust.1-22The relationship between structure and materials properties can be influenced by theservice conditions (environmental conditions). Name two engineering disasters thathave had tragic results and why they happened.Solution:Answers will vary. Two sample answers:The Titanic sank when it hit an iceberg. Hull plate and rivets of the ship were made ofthe strongest material to use at that time, but at room temperature. The material faileddue to its anisotropy and temperature sensitivity for when it was exposed to the frigidwaters during its voyage, behaved like glass (brittle).The Space Shuttle Challenger tragic flight when the rocket boosters exploded due to thesolid rocket booster (SRB) O-ring failure. The freezing temperatures of that morning hadthe O-rings behave like glass and the vibrations during lift-off cracked the O-rings andthe boosters exploded.1-23What is the difference between physical and mechanical properties? List three examplesfor each one.Solution:Physical properties are the properties of a material as it is found in nature such asdensity, thermal conductivity, electrical conductivity, luster, color, corrosion resistance,oxidation resistance, coefficient of thermal expansion (CTE) and magnetic permeability.Mechanical properties are properties that can be tested for such as strength (fatigue,impact, tensile, yield), ductility, stiffness, creep rupture, toughness and hardness.

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81-24The type of jet engine used on most large commercial aircraft is called a turbofan jetengine because it has a large wheel at the front of the engine that propels air rearward.Most of this air bypasses the engine, but bypass air significantly increases thrust andefficiency of these engines. Some engine manufacturers are now using carbon fiber-epoxy composites rather than traditional aluminum blades.(a) What materials properties do you think an engineer must consider when selecting amaterial for this application? Be as specific as possible.(b) What benefits do you think carbon fiber epoxy composites have compared toaluminum alloys? What limitations or possible downsides could there be to using acarbon fiber epoxy composite?Solution:(a) Properties that should be considered include the following: Tensile strength, impacttoughness, fracture toughness, modulus of elasticity and resistance to ultravioletradiation, which is a deteriorative property for polymers.(b) Potential benefits include significant weight reduction and greater stiffness overaluminum. The downsides include increase cost and most likely lower fracturetoughness.1-25You are an engineer working for a manufacturer of land-based gas turbines. Theseturbines are similar to jet engines, but they are used on land to provide power forelectricity generation and gas compression pipeline applications. Suppose that youwould like to apply a ceramic-based thermal barrier coating to the turbine blades in thefirst-stage turbine to increase the operating temperature and efficiency of the engine.(a) What difficulties might engineers experience in trying to design a ceramic coatingthat will be applied to a super alloy metal blade?(b) What properties should be taken into consideration when choosing a suitableceramic material for a coating? Be as thorough as possible.Solution:(a) Difficulties include a suitable method to apply and bond the ceramic to the metalblades. Coefficients of thermal expansion (CTE) for metals and ceramics differ greatlywhich would result in spallation of the ceramic coating.(b) Properties to be considered should be coefficient of thermal expansion (CTE),thermal conductivity, specific heat, melting temperature, impact toughness anddeteriorative properties.1-26We would like to produce a transparent canopy for an aircraft. If we were to use atraditional window glass canopy, rocks or birds might cause it to shatter. Design amaterial that would minimize damage or at least keep the canopy from breaking intopieces.

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9Solution:We might sandwich a thin sheet of a transparent polymer between two layers of theglass. This approach, used for windshields of automobiles, will prevent the “safety” glassfrom completely disintegrating when it fails, with the polymer holding the broken piecesof glass together until the canopy can be replaced.Another approach might be to use a transparent, “glassy” polymer material such aspolycarbonate. Some polymers have reasonably good impact properties and may resistfailure. The polymers can also be toughened to resist impact by introducing tinyglobules of a rubber, or elastomer, into the polymer; these globules improve the energy-absorbing ability of the composite polymer, while being too small to interfere with theoptical properties of the material.1-27You would like to design an aircraft that can be flown by human power nonstop for adistance of 30 km. What types of material properties would you recommend? Whatmaterials might be appropriate?Solution:Such an aircraft must possess enough strength and stiffness to resist its own weight, theweight of the human “power source,” and any aerodynamic forces imposed on it. Onthe other hand, it must be as light as possible to ensure that the human can generateenough work to operate the aircraft. Composite materials, particularly those based on apolymer matrix, might comprise the bulk of the aircraft. The polymers have a lightweight (with densities of less than half that of aluminum) and can be strengthened byintroducing strong, stiff fibers made of glass, carbon, or other polymers. Composites,having the strength and stiffness of steel, but with only a fraction of the weight, can beproduced in this manner.1-28You would like to place a three-foot diameter microsatellite into orbit. The satellite willcontain delicate electronic equipment that will send and receive radio signals fromearth. Design the outer shell within which the electronic equipment is contained. Whatproperties will be required, and what kind of materials might be considered?Solution:The shell of the microsatellite must satisfy several criteria. The material should have alow density, minimizing the satellite weight so that it can be lifted economically into itsorbit; the material must be strong, hard, and impact resistant in order to ensure thatany “space dust” that might strike the satellite does not penetrate and damage theelectronic equipment; the material must be transparent to the radio signals that providecommunication between the satellite and earth; and the material must provide somethermal insulation to ensure that solar heating does not damage the electronics.One approach might be to use a composite shell of several materials. The outsidesurface might be a very thin reflective metal coating that would help reflect solar heat.

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10The main body of the shell might be a light weight fiber-reinforced composite thatwould provide impact resistance (preventing penetration by dust particles) but wouldbe transparent to radio signals.1-29What properties should the head of a carpenter’s hammer possess? How would youmanufacture a hammer head?Solution:The head for a carpenter’s hammer is produced by forging, a metal working process; asimple steel shape is heated and formed in several steps while hot into the requiredshape. The head is then heat treated to produce the required mechanical and physicalproperties.The striking face and claws of the hammer should be hard—the metal should not dentor deform when driving or removing nails. These portions must also possess someimpact resistance, particularly so that chips do not flake off the striking face and causeinjuries.1-30You would like to select a material for the electrical contacts in an electrical switchingdevice that opens and closes frequently and forcefully. What properties should thecontact material possess? What type of material might you recommend? Would Al2O3be a good choice? Explain.Solution:The material must have a high electrical conductivity to ensure that no electrical heatingor arcing occurs when the switch is closed. High purity (and therefore very soft) metalssuch as copper, aluminum, silver, or gold provide the high conductivity. The device mustalso have good wear resistance, requiring that the material be hard. Most hard, wearresistant materials have poor electrical conductivity.One solution to this problem is to produce a particulate composite material composedof hard ceramic particles embedded in a continuous matrix of the electrical conductor.For example, silicon carbide particles could be introduced into pure aluminum; thesilicon carbide particles provide wear resistance while aluminum provides conductivity.Other examples of these materials are described in Chapter 17.Al2O3by itself would not be a good choice—alumina is a ceramic material and is anelectrical insulator; however, alumina particles dispersed into a copper matrix mightprovide wear resistance to the composite.1-31Aluminum has a density of 2.7 g/cm3. Suppose you would like to produce a compositematerial based on aluminum having a density of 1.5 g/cm3. Design a material that wouldhave this density. Would introducing beads of polyethylene, with a density of 0.95g/cm3, into the aluminum be a likely possibility? Explain.

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11Solution:In order to produce an aluminum-matrix composite material with a density of 1.5 g/cm3,we would need to select a material having a density considerably less than 1.5 g/cm3.While polyethylene’s density would make it a possibility, the polyethylene has a verylow melting point compared to aluminum; this would make it very difficult to introducethe polyethylene into a solid aluminum matrix—processes such as casting or powdermetallurgy would destroy the polyethylene. Therefore polyethylene would NOT be alikely possibility.One approach, however, might be to introducehollowglass beads. Although ceramicglasses have densities comparable to that of aluminum, a hollow bead will have a verylow density. The glass also has a high melting temperature and could be introduced intoliquid aluminum for processing as a casting.1-32You would like to be able to identify different materials without resorting to chemicalanalysis or lengthy testing procedures. Describe some possible testing and sortingtechniques you might be able to use based on the physical properties of materials.Solution:Some typical methods might include: measuring the density of the material (may help inseparating metal groups such as aluminum, copper, steel, magnesium, etc.),determining the electrical conductivity of the material (may help in separating ceramicsand polymers from metallic alloys), measuring the hardness of the material (perhapseven just using a file), and determining whether the material is magnetic ornonmagnetic (may help separate iron from other metallic alloys).1-33You would like to be able to physically separate different materials in a scrap recyclingplant. Describe some possible methods that might be used to separate materials such aspolymers, aluminum alloys, and steels from one another.Solution:Steels can be magnetically separated from the other materials; steel (or carbon-containing iron alloys) are ferromagnetic and will be attracted by magnets. Densitydifferences could be used—polymers have a density near that of water; the specificgravity of aluminum alloys is around 2.7; that of steels is between 7.5 and 8. Electricalconductivity measurements could be used—polymers are insulators while aluminum hasa particularly high electrical conductivity.1-34Some pistons for automobile engines might be produced from a composite materialcontaining small, hard silicon carbide particles in an aluminum alloy matrix. Explain whatbenefits each material in the composite may provide to the overall part. What problemsmight the different properties of the two materials cause in producing the part?

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12Solution:Aluminum provides good heat transfer due to its high thermal conductivity. It has goodductility and toughness, reasonably good strength, and is easy to cast and process. Thesilicon carbide, a ceramic, is hard and strong, providing good wear resistance, and alsohas a high melting temperature. It provides good strength to the aluminum, even atelevated temperatures. There may be problems, however, producing the material—forexample, the silicon carbide may not be uniformly distributed in the aluminum matrix ifthe pistons are produced by casting. We need to ensure good bonding between theparticles and the aluminum—the surface chemistry must therefore be understood.Differences in expansion and contraction with temperature changes may causedebonding and even cracking in the composite.1-35Investigate the origins and applications for a material that has been invented ordiscovered since you were bornorinvestigate the development of a product ortechnology that has been invented since you were born that was made possible by theuse of a novel material. Write one paragraph about this material or product. Provide alist of the references or websites that you used. You must use at least three references.Solution:Answers will vary.

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13Chapter 2: Atomic Structure2-1What is meant by the termcompositionof a material?Solution:The chemical make-up of the material.2-2What is meant by the termstructureof a material?Solution:The spatial arrangement of atoms or ions in the material.2-3What are the different levels of structure of a material?Solution:Atomic structure, short- and long-range atomic arrangements, nanostructure,microstructure, and macrostructure.2-4Why is it important to consider the structure of a material when designing andfabricating engineering components?Solution:The structure of the material at all levels will affect the physical and mechanicalproperties of the final product.2-5What is the difference between the microstructure and macrostructure of a material?Solution:A length scale of about 100,000 nm (100 μm) separates microstructure (less than100,000 nm) from macrostructure (greater than 100,000 nm).2-6(a) Aluminum foil used for storing food weighs about 0.3 grams per square inch. Howmany atoms of aluminum contained in one square inch of the foil? (b) Using thedensities and atomic weights given in Appendix A, calculate and compare the number ofatoms per cubic centimeter in (i) lead and (ii) lithium.Solution:(a)ᡀ〨ぇあ぀う= 䙦1 in.⡰䙧㐶0.31g Alin.⡰㑀㐶126.982mol Alg Al㑀䙸6.022 × 10⡰⡱1atomsmol䙹

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14ᡀ〨ぇあ぀う= 6.7 × 10⡰⡩Al atoms(b)ᡀ〨ぇあ぀う= 㐶11.361g Pbcm⡱㑀㐶1207.19mol Pbg Pb㑀䙸6.022 × 10⡰⡱1atomsmol䙹ᡀ〨ぇあ぀う= 33.0 × 10⡰⡩Pb atomscm⡱ᡀ〨ぇあ぀う= 㐶0.5341g Licm⡱㑀㐶16.94mol Lig Li㑀䙸6.022 × 10⡰⡱1atomsmol䙹ᡀ〨ぇあ぀う= 46.3 × 10⡰⡩Li atomscm⡱2-7(a) Using data in Appendix A, calculate the number of iron atoms in one ton (2000pounds). (b) Using data in Appendix A, calculate the volume in cubic centimetersoccupied by one mole of boron.Solution:ᡀ〨ぇあ぀う= 㐶20001lbton㑀㐶4541glb㑀㐶155.847mol Feg Fe㑀䙸6.022 × 10⡰⡱1atomsmol䙹ᡀ〨ぇあ぀う= 9.8 × 10⡰⡵Fe atomstonᡈ = 䙦1 mol B䙧㐶10.811g Bmol B㑀䙸12.36cm⡱Bg B䙹ᡈ = 4.58 cm⡱B2-8In order to plate a steel part having a surface area of 200 in.2with a 0.002 in.-thick layerof nickel: (a) how many atoms of nickel are required? (b) How many moles of nickel arerequired?Solution:(a)We start with the volume required:ᡈ = 䙦200 in.⡰䙧䙦0.002 in. 䙧㐶2.541cmin.㑀⡱= 6.55 cm⡱

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15ᡀ〨ぇあ぀う= 䙦6.55 cm⡱䙧㐶8.9021g Nicm⡱㑀㐶158.71mol Nig Ni㑀䙸6.022 × 10⡰⡱1atomsmol䙹ᡀ〨ぇあ぀う= 598 × 10⡰⡩atoms Ni(b)ᡀ぀あ〹〲う= 䙦6.55 cm⡱䙧㐶8.9021g Nicm⡱㑀㐶158.71mol Nig Ni㑀ᡀ぀あ〹〲う= 0.99 mol Ni2-9Defineelectronegativity.Solution:Electronegativity is the tendency of an atom to accept an electron (which has a negativecharge) and become an anion.2-10Write the electronic configuration of the following elements (a) tungsten, (b) cobalt, (c)zirconium, (d) uranium, and (e) aluminum.Solution:(a) W: [Xe] 4f145d46s2(b) Co: [Ar] 3d74s2(c) Zr: [Kr] 4d24s2(d) U: [Rn] 5f36d17s2(e) Al: [Ne] 3s23p12-11Write the electron configuration for the element Tc.Solution:Since Technetium is element 43:[Tc] = 1s22s22p63s23p64s23d104p65s24d52-12Assuming that the Aufbau Principle is followed, what is the expected electronicconfiguration of the element with atomic numberZ= 116?Solution:Using the Aufbau diagram produces:[116] = 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d107p4Or in shorthand:

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