Completed Chemistry.docx

ASSIGNMENT Course Code Course Name Programme Department Faculty

Chemistry B.Tech Mechanical Faculty of Engineering & Technology

Name of the Student

Sai Saradind T.

Reg. No

17ETME005071

Semester/Year Course Leader/s

2nd/2017 Anantha Ramaiah & Sunil

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Declaration Sheet Student Name Reg. No Programme

Semester/Year

Course Code Course Title Course Date

to

Course Leader

Declaration The assignment submitted herewith is a result of my own investigations and that I have conformed to the guidelines against plagiarism as laid out in the Student Handbook. All sections of the text and results, which have been obtained from other sources, are fully referenced. I understand that cheating and plagiarism constitute a breach of University regulations and will be dealt with accordingly.

Signature of the Student

Date

Submission date stamp (by Examination & Assessment Section)

Signature of the Course Leader and date

Signature of the Reviewer and date

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Contents ____________________________________________________________________________ Declaration Sheet ...................................................................................................................................... ii Contents .................................................................................................................................................... iii List of Tables .............................................................................................................................................. v List of Figures .............................................................................................................................................vi List of Symbols ..........................................................................................................................................vii Question No. 1 ........................................................................................................................................... 8 1.1 Overview: ......................................................................................................................................... 9 1.2 Solution to the question: ................................................................................................................. 9 1.3 Discussions /Suggestions/Views/Recommendations .................................................................... 13 1.4 Conclusions ........................................................................................Error! Bookmark not defined. Question No. 2 ......................................................................................................................................... 14 2.1 Overview: ....................................................................................................................................... 16 2.2 Solution to the question: ............................................................................................................... 17 2.3 Discussions /Suggestions/Views/Recommendations ........................Error! Bookmark not defined. 2.4 Conclusions ........................................................................................Error! Bookmark not defined. Question No. 3 .............................................................................................Error! Bookmark not defined. 3.1 Overview: ....................................................................................................................................... 19 3.2 Solution to the question: ............................................................................................................... 19 3.3 Discussions /Suggestions/Views/Recommendations .................................................................... 20 3.4 Conclusions .................................................................................................................................... 20 Question No. 4 .............................................................................................Error! Bookmark not defined. 4.1 Overview: ...........................................................................................Error! Bookmark not defined. 4.2 Solution to the question: ...................................................................Error! Bookmark not defined. 4.3 Discussions /Suggestions/Views/Recommendations ........................Error! Bookmark not defined. 4.4 Conclusions ........................................................................................Error! Bookmark not defined. Question No. 5 .............................................................................................Error! Bookmark not defined. 5.1 Overview: ...........................................................................................Error! Bookmark not defined. 5.2 Solution to the question: ...................................................................Error! Bookmark not defined.

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5.3 Discussions /Suggestions/Views/Recommendations ........................Error! Bookmark not defined. 5.4 Conclusions ........................................................................................Error! Bookmark not defined.

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List of Tables ____________________________________________________________________________

Table No. Table 1.1 Table 1.2 Table 2.1

Title of the table Title of the table Title of the table Title of the table

Pg.No. 12 14 18

< The table numbers have to be based on the chapter number>

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List of Figures ____________________________________________________________________________ Figure No. Figure 1.1 Figure 1.2 Figure 2.1

Title of the figure Title of the figure Title of the figure Title of the figure

Pg.No. 13 15 19

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List of Symbols ____________________________________________________________________________

Symbol A g V w

Description Current Acceleration due to gravity - 9.81 Voltage Width

Units Amp m/s2 Volts mm

< Arrange in alphabetical order>

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Question No. 1

Traditional methods to produce alloys involve mixing the elements and heating them above their melting points. In modern methods powder sintering method is used to produce various alloys but this leads to some toxic effects such as health hazards to the workers when inhaled. In this context debate on the statement: “Powder metallurgy is the future technology to produce engineering alloys”. Your debate should emphasize on:

A1.1. Comparison and contrast the traditional and powder metallurgy methods of preparing alloys A1.2. Current trends and challenges in powder metallurgy A1.3. Justification of the stance

Solution to Question No. 1: Solution A1.1: POWER METALLURGY:

Powder metallurgy (PM) is the production and utilization of metal powders. Powders are defined as particles that are usually less than 1000 nm (1 mm) in size. Most of the metal particles used in PM are in the range of 5 to 200 mm (0.2 to 7.9 mils). To put this in context, a human hair is typically in the 100 mm (3.9 mils) range Powders have a high ratio of surface area to volume and this is taken advantage of in the use of metal powders as catalysts or in various chemical and metallurgical reactions. While this article focuses on the use of powders to make functional engineering components, many metal powders are used in their particulate form. The three main reasons for using PM are economic, uniqueness, and captive applications. . For some applications that require high volumes of parts with high precision, cost is the overarching factor. A good example of this segment is parts for the automotive industry (where approximately 70% of ferrous PM structural parts are used). Powder metallurgy parts are used in engine, transmission, and chassis applications. Sometimes it is a unique microstructure or property that leads to the use of PM processing: for example, porous filters, self-lubricating bearings, dispersion strengthened alloys, functionally graded materials (e.g., titanium-hydroxyapatite), and cutting tools from tungsten carbide or diamond composites. Captive applications of PM include materials that are difficult to process by other techniques, such as refractory metals and reactive metals. Other examples in this category are special compounds such as molybdenum di silicide and titanium aluminide, or amorphous metals.

TRADITIONAL METALLURGY:

Traditional metallurgical processes are among the many ''old fashion'' practices that use nanoparticles to control the behavior of materials. Many of these practices were developed long before microscopy could resolve nanoscale features, yet the practitioners learned to manipulate and control microstructural elements that they could neither see nor identify. Furthermore, these early practitioners used that control to modify microstructures and develop desired material properties. Centuries old colored glass, ancient high strength steels and medieval organ pipes derived many of their desirable features through control of nanoparticles in their microstructures. Henry Sorby was among the first to recognize that the properties of rocks, minerals, metals and organic materials were controlled by microstructure. However, Mr. Sorby was accused of the folly of trying to study mountains with a microscope. Although he could not resolve nanoscale microstructural features, Mr. Sorby's observations revolutionized the study of materials. The importance of nanoscale microstructural elements should be emphasized, however, because the present foundation for structural materials was built by manipulating those features. That foundation currently supports several multibillion dollar industries but is not generally considered when the nanomaterials revolution is discussed. This lecture demonstrates that using nanotechnologies to control the behavior of metallic materials is

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almost as old as the practice of metallurgy and that many of the emergent nanomaterials technologists are walking along pathways previously paved by traditional metallurgists.

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Solution A1.2: WHY POWDER METALLURGY?

Powder Metallurgy is a technology which involves spending considerable time and effort in converting the starting material to the required powder form and then even further time and effort in “sticking” the material back together again to produce a more or less solid object. On describing the technology in these terms, it is not unreasonable therefore to pose the question “Why go to all this effort?” There are, in fact, many good reasons why Powder Metallurgy might be chosen as the preferred route for the manufacture of a product. In broad terms, these reasons separate into two categories: 

Cost effectiveness Powder Metallurgy is the most cost effective of a number of possible options for making the part



Uniqueness Some characteristic of the product (e.g. combination of chemical constituents, control over microstructure, control over porosity etc.) can be created by starting from a powder feedstock, which would be very difficult or sometimes impossible in conventional processing

Cost effectiveness Product cost effectiveness is by far the predominant reason for choosing Powder Metallurgy and is the main driver of the structural (or mechanical) parts sector. Powder Metallurgy wins the cost competition on the basis of its lower energy consumption, higher material utilisation and reduced numbers of process steps, in comparison with other production technologies. All of these factors, in turn, are dependent on Powder Metallurgy’s ability to reduce, or even possibly eliminate entirely, the machining operations that would be applied in conventional manufacture. In order to eliminate machining operations, Powder Metallurgy relies on its abilities to form complex geometrical shapes directly and to hold close dimensional tolerance control in the sintered product.

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Powder Metallurgy’s cost effectiveness generally also requires that the particular product be made in large production quantities. If production quantity requirements are too low, there would be no opportunity to amortise the costs of the (long-lasting) forming tooling over a sufficient numbers of parts or to avoid the loss of significant fractions of potential production time in tool changeover/setting operations. The production quantities at which Powder Metallurgy would be the process of choice is of course dependent on how difficult it would be to form the shape by a different route, but, in general, would be at least in the order of tens of thousands of parts per year.

Uniqueness Product uniqueness can be delivered by Powder Metallurgy in a number of different ways: 1. Processing combinations of materials that would otherwise be impossible to mix Powder Metallurgy allows the processing, in an intimate mixed form, of combinations of materials that would be conventionally regarded as immiscible. Well-established examples of this type of Powder Metallurgy application are: 

Friction materials for brake linings and clutch facings in which a range of non-metallic materials, to impart wear resistance or to control friction levels, are embedded in a copper-based or iron-based matrix.



Hardmetals or cemented carbides, used for cutting tools, forming tools or wear parts. These comprise a hard phase bonded with a metallic phase, a microstructure that can only be generated through liquid phase sintering at a temperature above the melting point of the binder. Tungsten carbide bonded with cobalt is the predominant example of such a material, but other hardmetals are available that include a range of other carbides, nitrides, carbonitrides or oxides and metals other than cobalt can be used as the binder (Ni, Ni-Cr, Ni-Co etc.)



Diamond cutting tool materials, in which fine diamond grit is uniformly dispersed in a metallic matrix. Again, liquid phase sintering is employed in the processing of these materials.



Electrical contact materials e.g. copper/tungsten, silver/cadmium oxide.

2. Processing of materials with very high melting points Powder Metallurgy enables the processing of materials with very high melting points, including refractory metals such as tungsten, molybdenum and tantalum. Such metals are very difficult to produce by melting and casting and are often very brittle in the cast state. The production of tungsten billet, for subsequent drawing to wire for incandescent lamps, was one of Powder Metallurgy’s very early application areas.

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3. Products with controlled levels of porosity Powder Metallurgy enables the manufacture of products with controlled levels of porosity in their structure. Sintered filter elements are examples of such an application. The other prime example is the oil-retaining or self-lubricating bearing, one of Powder Metallurgy’s longest established applications, in which the interconnected porosity in the sintered structure is used to hold a reservoir of oil.

4. Products with superior properties In some specific applications, the generation of superior properties, often through superior control over microstructure, is possible by Powder Metallurgy processing as opposed to conventional casting or wrought routes. Good examples in this category of application are: 

Magnetic materials Virtually all hard (permanent) magnets and around 30% of soft magnets are processed from powder feedstocks.



High speed steels The finer and more controlled microstructure from a Powder Metallurgy processed material provides superior toughness and cutting performance than wrought products.



Nickel- or cobalt-based superalloys Nickel- or cobalt-based superalloys are used for aero-engine applications, in which Powder Metallurgy processing can deliver compositional ranges and microstructural control not achievable conventionally and therefore an enhancement in operating temperature and performance.

A1.3 Justification:

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Question No. 2 B.1

(10 Marks)

During the design of a fastener, a designer must understand the material properties. In one of such design, a designer had used a passivated 304 stainless steel bolt to connect brass and Aluminium plates. After few months, it was found that both brass and Aluminium were found to corrode severely where they had contact with stainless steel. B1.1 Identify and discuss the types of corrosion that might have caused the materials to corrode. B1.2 Suggest the precautions that could have been taken during the design with justification.

B.2

(10 Marks)

Dinitrogen pentoxide is the chemical compound with the formula N2O5 and it is an unstable and potentially a dangerous oxidizer. It decomposes at lower temperature and produces nitrogen dioxide (NO2) and oxygen (O2). The balanced equation for this reaction is given below: 2N2O5(sol) 4NO2 (sol)+ O2 (g) A student has done the kinetic study of the decomposition of dinitrogen pentoxide and the observations made by him are listed in Table 1.

B2.1 Identify the rate of reaction using graphical method with the help of Microsoft excel software. B2.2 Calculate the rate constant of this reaction. B2.3 Deduce the rate law for this reaction. B2.4 Calculate the half-life of the reaction.

B.3

(10 Marks)

2-chloro 2-methyl propane undergo hydrolysis in the presence of dilute hydrochloric acid produces 2methyal propan-2-ol and the reaction is given below

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This reaction is being carried out at different temperatures and the corresponding rate constant values are listed in Table 2.

B3.1 Discuss the reason behind the increase in the rate constant with the increase in the temperature. B3.2 Determine the activation energy of this reaction from the data given in Table 2.

B.4

(10 Marks)

Metal finishing entails a wide variety of processes which provide the surfaces of manufactured products with a number of desirable physical, chemical and appearance qualities. Every manufactured or fabricated product made of metal or having metal components will feature some type of metal finishing. Several wastes such as mercury and chromium that are hazardous to human health and the environment are commonly generated by the electroplating industry. Chromium coating is one of the important metal finishing technique used widely in various industries. Most of the automobile components will use hard core chromium plating process. However this will also involve many health issues. B4.1 Discuss the conditions for hard core chromium plating and health hazards during the plating process. B4.2 Discuss any one new coating method that can be adopted to reduce waste and hazards in plating industry.

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Solution to Question No. 2: B1 Solution B1.1

The type of corrosion caused is Galvanic Corrosion , The issue of corrosion poses an extreme concern in design. One of the first questions a designer must address when analyzing a fastener application is whether the fastener will be subjected to a corrosive attack during service. It is important to understand that there are several different types of corrosion including galvanic corrosion, concentration-cell corrosion, stress corrosion, fretting corrosion, pitting, and oxidation. The most common form of corrosion is rust (oxidation) associated with steel structures and fasteners, although the effects of corrosive attack can be seen in many other structural materials. Corrosion can be thought of as an electro-chemical action in which one metal is changed into a chemical or simply eaten away. When two metals are in contact with each other in the presence of some electrolyte, the less active metal will act as the cathode and attract electrons from the anode. The anode is the material which corrodes. A simple means of visualizing what is occurring is to consider the action of a battery. If two metals are immersed in an acid, a saline, or an alkaline solution, a battery is formed. This battery produces a flow of electrons between the two metals. The flow of electrons continues as long as the metals exist, the solution remains acidic, saline, or alkaline, and as long as a conductive path connects the two metals. In the case of galvanic corrosion, the combination of two dissimilar metals with an electrolyte is all that is needed to form a reaction. The use of dissimilar metals in structural design is fairly common, particularly cases where the fastener material is different from the structure being joined. Furthermore, the electrolyte may be present in the form of rain, dew, snow, high humidity, ocean salt spray, or even air pollution. Thus, designers must take into account the reactivity of the metals being joined.

All metals have some kind of electrical potential. The “Galvanic Series of Metals and Alloys” chart above provides a realistic and practical ranking of metallic electrical potentials. The alloys near the bottom are cathodic and unreactive; those at the top are most anodic. The various metals which are grouped together are reasonably compatible when used together; those in different groups may cause a corrosion problem. Some metals, especially those with significant contents of nickel and chromium, are included in the table in both their active and passive conditions. Passivation, (i.e.: surface cleaning and sealing) lowers the metals electrical potential and improves its corrosion behavior. As the series suggests, steel and aluminum are relatively compatible, but if brass and steel

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contact, the steel will corrode because it is more anodic than the brass. If brass and aluminum plates are connected by a passivated 304 stainless steel bolt, both the brass and the aluminum will corrode severely where they touch the stainless steel because they are much more anodic than stainless steel. The aluminum plate will corrode more heavily due to it being more anodic to stainless steel than brass is. The aluminum will also corrode where its exposed surface contacts the brass plate because brass is more cathodic. A Plating Compatibility Chart is provided below that may be used to aid with fastener selection based on galvanic reaction.

Solution B1.2:

Minimizing Galvanic Corrosion

Use metals that are not dissimilar Prevent dissimilar metals form becoming electrically connected by water Keep small anodes from contacting large cathodes. The rate of corrosion depends on the surface area of the anode with respect to the cathode. The smaller the surface area of the anode relative to the surface area of the cathode, the more concentrated the flow of electrons at the anode and the faster the rate of corrosion. The larger the anode's surface area in relation to the cathode, the more spread out of the flow of electrons and the slower the rate of the anode's corrosion. The application of a protective metallic coating, known as a sacrificial coating, can provide galvanic protection to the base metal when the coating is measurably more anodic than the base metal. galvanic corrosion will take place with the anodic material when the base material is exposed. The extent to which a sacrificial coating can continue to protect the base metal is directly related to the thickness of the coating. Metallic coasting that are not sacrificial, as well as paint coatings, plastic, or other non-metallic barriers can also significantly reduce galvanic corrosion. however, when using a paint coating, it is important to realize that if the base metal becomes exposed through a small scratch in the paint, the base metal could rapidly corrode if it becomes the anode in a reaction with a nearby dissimilar metal with a large surface area. Preventing Corrosion in Fasteners

Galvanic corrosion is obviously a concern in the use of metal fasteners such as bolts, screws, and welds. Because fasteners have a much smaller surface area than the materials they fasten, fasteners that take on the role of the anode will be at risk of rapid corrosion and thus should be avoided. For example, zinc-coated fasteners should only be used to connect steel coated with aluminum, zinc, and galvalume, as these are very close on the Galvanic Series and are not generally at risk of corrosion when placed together. On the other had, zinc-coated or aluminum-coated fasteners should not be used to attach copper or stainless-steel panels. To minimized the risk of galvanic corrosion of fasteners, match the surface metal on the fastener with that on the metal it will fasten. The most desired combination of large anode with small cathode; in other words, fasteners such as bolts and screws should be made of the metal less likely to corrode, or the more cathodic.

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Corrosion of Panels and Trim in Contact with Treated Wood

Do not allow aluminum, aluminum-coated, and galvalume-coated panels and trim to come into direct contact with wood preservatives containing copper, mercury, or fluorides. Avoid direct contact between bare metal panels and treated lumber where condensation will frequently form on the metal surface in contact with the lumber, and where the wood treatment is more noble than the metal surface. Use an appropriate barrier to separate metal panels and treated lumber.

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B2 Solution B2.1:

Time(s) 0 600 1200 1800 2400 3000 36000

Concentration/[A] 0.0365 0.0274 0.0206 0.0157 0.0117 0.00860 0.00640

Ln[A] -3.3104 -3.5972 -3.8824 -4.1540 -4.4481 -4.75599 -5.0514

1/[A] 27.39 36.49 48.54 63.69 85.47 116.27 156.25

We found ln[A] and 1/ln[A] and kept the values according to the concentrations each So, in order to find the order of the reaction, The Graph we get in Excel is as:

We get a straight line in the graph for the graph of Time versus Ln[A], which gets to us that it is a First Order Reaction.

Solution B2.2:

To find the rate of the reaction, we have to check it’s Order. In the reaction after solving it we get the Order to be 1. Therefore, [A]=[𝐴]0 𝑒 −𝑘𝑇 is the equation to find K if it is a first order rate reaction. 0.0064=0.0365𝑒 −𝑘∗3600 <Subject Title>

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Hence we get the value for K as K(rate of reaction) = 0.000487809.

Solution B2.3: In complex reactions the rate expression written on the basis of the overall balanced equation has no significance at all. It merely represents a theoretical expression. The true rate expression for such complex reactions can be evaluated on the basis of the experimental data only. For example, 2N2O5(sol)

= 4NO2 (sol)+ O2

(Experimental1y, it has been observed that the rate of this reaction is proportional to the product of single concentration term of NO2and O2. Thus, experimental rate of there action or the actual rate of reaction is given as rate = k [NO2] [O2] A mathematical expression that gives the true rate of a reaction in terms of concentration of the reactants, which actually influence the rate, is called Rate Law. For a general reaction, aA + bB = cC + dD where a, b, c and d are the stoichiometric coefficients of reactants and product’>. The rate expression for this reaction is Rate = [𝐴]𝑥 +[𝐵]𝑦 = K[𝐴]𝑥 [𝐵]𝑦 It is known as rate constant or velocity constant or specific reaction rate. If the concentration of all reacting species is taken as unity then, rate = k reaction rate.

B2.4

Half Life of a first order reaction is: 𝑡1/2 =

0.693 𝑘

Where k is 0.000487809. So, 0.693 𝑡1/2 = 0.000487809 𝑡1/2 = 1420.637sec.

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B3 Solution B3.1: The rate constant goes on increasing as the temperature goes up, but the rate of increase falls off quite rapidly at higher temperatures. A catalyst will provide a route for the reaction with a lower activation energy. ... And the rate constant k is just one factor in the rate equation.

The rate equation shows the effect of changing the concentrations of the reactants on the rate of the reaction. What about all the other things (like temperature and catalysts, for example) which also change rates of reaction? Where do these fit into this equation? These are all included in the so-called rate constant - which is only actually constant if all you are changing is the concentration of the reactants. If you change the temperature or the catalyst, for example, the rate constant changes. Using the Arrhenius equation The effect of a change of temperature

You can use the Arrhenius equation to show the effect of a change of temperature on the rate constant - and therefore on the rate of the reaction. If the rate constant doubles, for example, so also will the rate of the reaction. Look back at the rate equation at the top of this page if you aren't sure why that is. What happens if you increase the temperature by 10°C from, say, 20°C to 30°C (293 K to 303 K)? The frequency factor, A, in the equation is approximately constant for such a small temperature change. We need to look at how e-(EA / RT) changes - the fraction of molecules with energies equal to or in excess of the activation energy. Let's assume an activation energy of 50 kJ mol-1. In the equation, we have to write that as 50000 J mol-1. The value of the gas constant, R, is 8.31 J K-1 mol-1. At 20°C (293 K) the value of the fraction is:

By raising the temperature just a little bit (to 303 K), this increases:

You can see that the fraction of the molecules able to react has almost doubled by increasing the temperature by 10°C. That causes the rate of reaction to almost

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double. This is the value in the rule-of-thumb often used in simple rate of reaction work. Solution B3.2: To find the Activation Energy, from the given table

So, calculate ln[k] and 1/t Temperature(t) 293 303 313 323 333

Rate Constant(k) 364 488 666 898 1282

Ln[k] 5.897 6.190 6.501 6.8001 7.156

1/t 0.0034 0.0033 0.0031 0.0030 0.0030

Hence, Slope= rise/run Slope= (5.897-7.156)/(0.0034-0.0030) Slope = -3147.5 Therefore, Activation Energy is given by, 𝐸𝑎 = 𝑅 ∗ 𝑆𝑙𝑜𝑝𝑒 = R* -3147.5 = -3147.5* 8.315 𝐸𝑎 =-26171.4625 kJ/Mol

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B4 Solution B4.1: Solution B4.2: The surfaces of the cavity and core are likely to be oxidized (rusted) and corroded by the volatile components from the molded material or from moisture content in the atmosphere. Considering the mold release of the molded article, it is necessary that the surface of the cavity is carefully polished and is maintained in a shining condition. Plating the surface of the cavity is used as a measure for preventing oxidization or corrosion. Hard chromium plating is a typical method of plating among the different varieties of plating. Hard chromium plating has good wear resistance and corrosion resistance. The hardness of the film on the surface is 700 to 1000 HV, and the surface has a white metallic glossiness. To carry out the plating, the work to be plated is immersed in a plating solution made of chromic acid anhydride, sulfuric acid, etc., and an electric current is passed to form an electroplated film. The plated film is a robust passivated film of a base metal in air. Since the surface energy of the plated film is low, it has the property of being hard to be adhered to by other materials. Therefore, it can also be said that it has the property of making it easy for the plastic molded article to be released from the mold. In order to carry out plating skillfully, it is recommended to carefully polish the part of the surface that is to be plated, thereby putting it in a state in which the plating can adhere to it easily. In fields other than molds, this type of plating is used for preventing rust in the parts for food production machines, mill rolls, and for preventing rusting of machine parts. In general, since the waste plating liquid treatment and management of plating liquid are important from the point of view of pollution prevention, in most cases, the work of hard chromium plating is entrusted to specialized companies.

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Bibliography ________________________________________________________________________________ 1. Kinicki and Williams Irwin. (2008) Management, McGraw Hill. 2. Decenzo David and Robbin Stephen A. (1996) Personnel and Human Reasons Management, Prentice Hall of India. 3. J.A.F. Stoner, Freeman R. E and Daniel R Gilbert. (2004) Management, 6th Edition, Pearson Education. 4. Fraidoon Mazda. (2000) Engineering Management, Addison Wesley. All referencing, bibliography needs to be done as described in the following article: http://www.msruas.ac.in/pdf_files/VCBlogs/Academic%20Good%20Practices.pdf

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