CHAPTER 2 LITERATURE REVIEW
2.1. Basics of Oxidation
Oxidation is an electrochemical reaction in which metals lose electrons to oxidizing reactants [5] [7][8] [6] [9]. Oxidation produces a crystallographic ally distinct solid compound as there action product. Thermodynamically, oxidation reactions with air or oxygen can be represented by: xM + y/2 O2 → M_x O_y
Where x and y are integers, M metals, and M_x O_y the metal oxides .The change in free energy, AG, can be expressed as [10]. Oxidation of iron has been investigated and well understood. When iron oxidized in air at higher or elevated temperature layers of oxide scale are formed on the upper surface of the metal. Composition of the scale layers depends on the temperature [11]. As per the iron oxygen phase diagram, there is no wustite (FeO) formed if the iron is oxidized below 570C. A two layer oxide scale of magnetite (Fe3O4) and hematite (Fe2O3) are probably formed below this temperature with
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Selected properties of the formed iron oxides are given in Table2.2 [6][17][15]. In contrast to Fe1-XO, and Fe3O4, which are “cation-deficient” compounds and α-Fe2O3 has an “anion deficient” lattice [16][17]. Based on the data of Table2.1 and Table2.2, unit cell structures of iron oxides are depicted in below Figure2.3 using Electron Microscopy Image Simulation On-Line [19 ].Figure2.4 shows the three dimensional crystal structures for all the iron oxide [17] .These structures can be also expressed by the close packed array as in below Figure2.5 [19].). The characteristics of each oxide will be addressed in the following
Iron is naturally iron oxide and purified iron rapidly returns to a similar state when exposed to air and water. This whole process can be seen below in figure 3 – ‘The corrosion
2-ethyl-1,3-hexanediol. The molecular weight of this compound is 146.2g/mol. It is converted into 2-ethyl-1-hydroxyhexan-3-one. This compounds molecular weight is 144.2g/mol. This gives a theoretical yield of .63 grams. My actual yield was .42 grams. Therefore, my percent yield was 67%. This was one of my highest yields yet. I felt that this was a good yield because part of this experiment is an equilibrium reaction. Hypochlorite must be used in excess to push the reaction to the right. Also, there were better ways to do this experiment where higher yields could have been produced. For example PCC could have been used. However, because of its toxic properties, its use is restricted. The purpose of this experiment was to determine which of the 3 compounds was formed from the starting material. The third compound was the oxidation of both alcohols. This could not have been my product because of the results of my IR. I had a broad large absorption is the range of 3200 to 3500 wavenumbers. This indicates the presence of an alcohol. If my compound had been fully oxidized then there would be no such alcohol present. Also, because of my IR, I know that my compound was one of the other 2 compounds because of the strong sharp absorption at 1705 wavenumbers. This indicates the presence of a carbonyl. Also, my 2,4-DNP test was positive. Therefore I had to prove which of the two compounds my final product was. The first was the oxidation of the primary alcohol, forming an aldehyde and a secondary alcohol. This could not have been my product because the Tollen’s test. My test was negative indicating no such aldehyde. Also, the textbook states that aldehydes show 2 characteristic absorption’s in the range of 2720-2820 wavenumbers. No such absorption’s were present in my sample. Therefore my final product was the oxidation of the secondary alcohol. My final product had a primary alcohol and a secondary ketone
Compared with the accepted value of –601.8 kJ/mol Mg, our experimental error was 2.46%. Introduction In this investigation the change in enthalpy will be determined from the following equation: 2Mg + O2 ® 2MgO, but in an indirect manner. Magnesium metal burns on a bright, extremely hot flame to produce magnesium oxide. It would be difficult to measure the heat of the reaction since the reaction is rapid and occurs at a high temperature (LeMay et al, 1996).
The purpose of this lab was to to cycle solid copper through a series of chemical forms and return it to its original form. A specific quantity of copper undergo many types of reactions and went through its whole cycle, then returned to its solid copper to be weighted. We observed 5 chemical reactions involving copper which are: Redox reaction (which includes all chemical reactions in which atoms have their oxidation state changed), double displacement reaction, precipitation reaction, decomposition reaction, and single displacement reaction.
Metals contain a sea of electrons (which are negatively charged) and which flow throughout the metal. This is what allows electric current to flow so well in all metals. An electrode is a component of an electric circuit that connects the wiring of the circuit to a gas or electrolyte. A compound that conducts in a solution is called an electrolyte. The electrically positive electrode is called the anode and the negative electrode the cathode.
Pure iron has a hardness that ranges from 4 to 5. It is soft and ductile. Iron can be easily magnetized at ordinary temperatures and at 790°C the magnetic property disappears. Pure iron melts at about 1535°C, boils at 2750°C, and has a specific gravity of 7.86. Chemically, iron is an active metal. When exposed to humid air, iron forms a reddish-brown, flaky, decay known as rust.
Chromite is not magnetic and has a more resinous luster. Hematite has a red streak and it is not magnetic or weakly magnetic. Ilmenite has a black streak and weak magnetism. Cassiterite has a high specific gravity and brown color. Magnetite has a black streak and it is very magnetic.
Lead reacts the slowest of these and aluminum the fastest. Although aluminum oxidizes and makes a metal oxide coating, this coating is very thin and hard, so it protects the aluminum from corroding
in 5cm³ of water and add 4cm³ of ethanol. We had tom pour this mixture
It involves collisions between the free electrons, the fixed. particles of the metal, other free electrons and impurities. These collisions convert some of the energy that the free electrons are. carrying heat, which means that electrical energy is lost. Apparatus: I will be using an Ammeter.
The basis for the understanding of the heat treatment of steels is the Fe-C phase diagram. Because it is well explained in earlier volumes of Metals Handbook and in many elementary textbooks, the stable iron-graphite diagram and the metastable Fe-Fe3 C diagram. The stable condition usually takes a very long time to develop, especially in the low-temperature and low-carbon range, and therefore the metastable diagram is of more interest. The Fe-C diagram shows which phases are to be expected at equilibrium for different combinations of carbon concentration and temperature. We distinguish at the low-carbon and ferrite, which can at most dissolve 0.028 wt% C at 727 oC and austenite which can dissolve 2.11 wt% C at 1148 oC. At the carbon-rich side we find cementite. Of less interest, except for highly alloyed steels, is the d-ferrite existing at the highest temperatures. Between the single-phase fields are found regions with mixtures of two phases, such as ferrite + cementite, austenite + cementite, and ferrite + austenite. At the highest temperatures, the liquid phase field can be found and below this are the two phase fields liquid + austenite, liquid + cementite, and liquid + d-ferrite. In heat treating of steels the liquid phase is always avoided. Some important boundaries at single-phase fields have been given special names. These include: the carbon content at which the minimum austenite temperature is attained is called the eutectoid carbon content. The ferrite-cementite phase mixture of this composition formed during cooling has a characteristic appearance and is called pearlite and can be treated as a microstructural entity or microconstituent. It is an aggregate of alternating ferrite and cementite particles dispersed with a ferrite matrix after extended holding close to A1. The Fe-C diagram is of experimental origin. The knowledge of the thermodynamic principles and modern thermodynamic data now permits very accurate calculations of this diagram.
By adding up to 2%,of carbon it makes the steel tough and strong. Although it’s tough and strong, it is able to bend. To make sure that the metal doesn’t rust, it has a zinc coating on it. Iron is 26 on the periodic table,and considered an “transition metal,” meaning that it is ductile and malleable, and conduct electricity and heat. ... “Some other elements that are similar to iron are cobalt and nickel. They are the only elements known to produce a magnetic field.” Zinc is 30 on the periodic table and it is also a transition metal like iron. “The first iron used by humans is likely to have come from meteorites.” A meteorite is a meteor that survives its passage through the earth's atmosphere such that part of it strikes the ground. More than 90 percent of meteorites are of rock, while the remainder consist wholly or partly of iron and nickel. Meteors are believed to have been from the asteroid belt of Mars and
Mann, M., 2013. Mind Action Series Physical Sciences 12 Textbook and Workbook. Sanlamhof: Allcopy Publishers.
Photocatalysis refers to the oxidation and reduction reactions on semiconductor surfaces, mediated by the valence band holes and conduction band electrons, which are generated by the absorption of ultraviolet or visible light radiation. Pairs of photo-generated hole (h+) and electron (e-) induce the formation of aggressive species such as hydroxyl or superoxide radicals from the moisture and atmospheric oxygen. These species are strong enough to oxidize and decompose organic materials or smelling gas and kill bacteria (see Fig 1). Several metal