2.3.2 Ammonium Perchlorate Decomposition The crystal structure of pure AP in the space is presented at Figure 19 where the oxygen atoms are shown in red, the chlorine atoms in yellow, the nitrogen atoms in blue and hydrogen atoms in white [40]. Figure 19: Ammonium perchlorate crystal structure. The self-deflagration rate of ammonium perchlorate (AP) at typical pressures is of the same order as the burning rate of many AP-based propellants. Therefore, the AP deflagration may be a fine controlling factor for propellant burning rate. The deflagration of pure AP has been investigated intensively in an effort to achieve a basic understanding of this process and thus of the combustion of solid rocket propellants which contain AP as the oxidizer. Around 240 °C, the phase-transition starts to occur where orthorhombic structure is converted into cubic one accompanied by an endothermic reaction at about 247 °C (520 K) (Figure 22). Under dynamic heating conditions AP decomposition becomes near completing at about 400°C. At temperature above 450 °C, the thermal decomposition of AP is very fast. After an induction period it shows a sudden rise in pressure which is often accompanied by a flash of light and rapid burning. This phenomenon is known as thermal explosion of AP [31]. Figure 22: Thermal decomposition process of AP measured by DTA. Pure ammonium perchlorate also characterized by the following [25]: Its reported adiabatic flame temperature ≈ 1400 K [40]. Its pressure exponent is high, around 0.77 between 20 and 100 bar. Its exothermic reactions in the condensed phase occur at 297 to 427 °C approximately. Its reported activation energy values are in the range of 62.8-172 kJ/mole [33, 40]. The reaction between ammonia and perchloric acid which produced by AP decomposition occurs at the surface, provides oxidizing species and its reaction order is about two. The studies on the decomposition of AP (Figure 23) divided into four temperature ranges (heating rates lower than 10 °C/min), two in the orthorhombic form and two in the cubic form. These are as follows [26, 31, 33, 40]. Figure 23: Ammonium perchlorate decomposition
As shown in Fig. 5, the final pH of the NaClO-NH3 solution after simultaneous removal are 5.4, 6.9, 7.2, 7.5, 8.5, 9.6, 10.7, 11.5 and 12.8 with respect to the initial pH of 5, 6, 7, 8, 9, 10, 11, 12 and 13, from which, an interesting law can be concluded as that if the initial pH is an acidic, the final pH is slightly increased; but if the initial pH is an alkaline, the final pH is declined. NaClO-NH3 is macromolecule compounds with a large inter surface area. It contains abundant functional groups such as hydroxyl (OH), carboxyl (COO), quinone, amino (–NH2), etc, which determines that NaClO-NH3 is a salt of strong base and weak acid, as well the ionization equilibrium and hydrolytic equilibrium would be complicated. When the pH of the NaClO-NH3 solution was acidic, the functional groups such as OH, COO and NH2- would react with H+ to generate the NH3 sediment, resulting in a decrease of inter surface area owing to the block and a great loss of NaClO-NH3, then the NOx removal as well as the duration time was decreased. As for the increase of the final pH in the acidic conditions, this was a result of the consumption of H+ by NaClO. The decrease of the
In the demo experiment, we placed 10 grams of Ammonium dichromate in the form of a solid before starting the experiment. When the experiment begins the Ammonium dichromate is burned up and then produces Chromium (III) oxide as a solid, Nitrogen gas and water in form of a gas. In the experiment, we combined Zinc Chloride and Sodium Sulfide in which both chemicals are aqueous. The result of the combination was Zinc Sulfide a solid and Sodium Chloride an aqueous solution. In the alternate experiment, we combined Lead (II) Nitrate and Potassium Iodide in which both chemicals are aqueous. The result of the combination was Lead (II) Iodide and Potassium Nitrate.
The esterification procedure was performed first. To begin the lab, the heating mantle was set at the 6 setting, and the hot plate heat was turned on to low. In a round bottom flask, 6.1 g of benzoic acid and 21 mL of MeOH were added into the flask. Once this was added to the flask, 2 mL of sulfuric acid was added and poured carefully down the side of the flask. It was noted that after the addition of the sulfuric acid there was heat production in the flask. The contents were swirled and a boiling chip was added into the flask. The flask was connected to the hood by a clamp. Water was then ran through the condenser and connected to the round bottom flask to begin refluxing the contents in the flask. The mixture was gently heated at reflux for one hour.
Ammonium nitrate was a key ingredient in a bomb that killed hundreds of people. It is an odorless crystal salt that can be either white or grey. It is created by a combination of ammonia and nitric acid. (ammonium Nitrate fact sheet). The primary uses for this chemical are fertilizers and cold packs, as well as military explosives (Mathews J, 2014). Not only is it an oxidizer but under enough heat and pressure, it can explode (ammonium Nitrate fact sheet). This explosive property leads to it being labeled a hazardous chemical in toxicology reports. In the past it has been a part of terrorism attacks such as the Oklahoma City bombing and accidental explosions in fertilizer factories. The Oklahoma City bombing is known as
The pure compound melting point should be in the range of 169-172 ℃. During this lab practical Paracetamol- acetaminophen will be synthesis, purified and recrystallized again. The purpose of the experiment was to learn basic recrystallization techniques that include hot and cold filtration
The aim of this experiment was to investigate the affect of the use of a catalyst and temperature on the rate of reaction while keeping all the other factors that affect the reaction rate constant.
Castka, J. F., Metcalfe, H. C., Davis, R. E., & Williams, J. E. (2002). Modern Chemistry. New York: Holt, Rinehart and Winston.
Looking at the table of results above and the graph, it is shown that the higher the temperature got, the shorter the reaction time. The obtained results have been plotted on a line graph of the temperature of hydrochloric acid (y-axis) against reaction time (x-axis). This line graph in fig.2 also clearly shows that as the temperature increases, so does the speed of the reaction, shown by a reduction in the time taken. This corroborates the collision theory, where as the temperature of particles increase, the particles gain more kinetic energy and react with each other upon collision. This is shown as to happen in the hydrochloric acid, where the hydrochloric acid particles collide more with the particles of the magnesium ribbon as the temperature was increased. The above graph shows a gradual sloping curve, which gets steeper at higher temperatures. This shows that the reaction will reach a peak rate of activity as the gaps between the temperature and reaction times continue to decrease. The experiment fulfills the aim and clearly shows that as the temperature of a reaction is increased so does it’s rate of reaction, proving the hypothesis to be correct.
Pyrolysis is a rapid thermal decomposition process of organic biomass, in absence or little supply of oxygen, brought about by high temperatures into useful biofuel products such as pyrolysis oil, ethanol, biodiesel, methanol etc. During the process, large hydrocarbon molecule’s chemical composition structure breaks down into relatively smaller molecules into solid (char), liquid or gas phase (Figure 1). The process is very similar to many other biomass decomposition processes such as torrefaction, carbonization, devolatilization etc. however pyrolysis cannot be compared to gasification due to external activation required for gasification.
Hydrogen peroxide decomposes into water and oxygen upon heating or in the presence of numerous substances, particularly salts of such metals as iron, copper, manganese, nickel, or chromium. It combines with many compounds to form crystalline solids useful as mild oxidizing agents; the best-known of these is sodium perborate (NaBO2H2O23H2O or NaBO34H2O). With certain organic compounds, hydrogen peroxide reacts to form hydroperoxides or peroxides, several of which are used to initiate polymerization reactions. In most of its reactions, hydrogen peroxide oxidizes other substances, although it is itself oxidized by a few compounds, such as potassium perm...
On further cooling the χT curve shows a sudden increase to 1.23 cm3.K.mol-1 at T=21 K followed by a sharp decrease down to 0.71 cm3.K.mol-1 at 5 K. The χT maximum de...
Temperature has a strong effect on nitrifying bacteria, as in the case of heterotrophic aerobic bacteria. The temperature dependence for the nitrification process corresponds to an Arrhenius equation, at least below 30 °C. At higher temperatures (30-35 ° C), the growth rate of nitrifying bacteria is constant and Begins to decrease between 35 and 40 °C. The two-stage biological nitrification process is a two-sludge system which is generally used when ammonia Disposal is subject to advanced treatment. The process is also used prior to biological denitrification systems where nitrate removal is required. The first step of the two-step process is typically a high-throughput activated sludge that is designed to achieve at least 75% to 85% elimination of carbonated BOD5. By realizing this Level of reduction of BOD5 in the first stage, conditions can be developed in the second step to improve nitrification. The nitrification of ammonia into nitrate occurs chiefly in the second stage. Nitrification is realized in a two-stage process by the biological activities of two specific groups of bacteria known as Nitrosomonas and
The process need toluene and hydrogen as a main reactor. Then, toluene and hydrogen are converted in a reactor packed with catalyst to produce benzene and methane. This reaction is exothermic and the operating conditions are 500 0C to 660 0C, and 20 to 60 bar of pressure. This process begins with mixing fresh toluene with a stream of recycle unreacted toluene, and the mixing is achieved in a storage tank. Then, the toluene is pumped to combine it with a stream of mixed hydrogen and fresh hydrogen gas. The mixture of toluene and hydrogen is preheated before it is introduce to the heater or furnace. In the furnace, the stream is heated to 600 0C, then introduced into the reactor. Basically, the main reactions occurs in the reactor.
An Investigation into the Decomposition of Hydrogen Peroxide Aim: To investigate the rate of decomposition of H2O2 with different amounts of catalyst (MnO2). Hypothesis: When H2O2 and a catalyst are mixed together, the catalyst would break down H2O2 into water and oxygen. This will result in bubbles being produced. With the data of these oxygen bubbles, the rate at which H2O2 decomposed could be found out. 2H2O2 (l) à2H2O + O2 The controlwould be to maintain the same temperature (room temperature) and to use the same amount of hydrogen peroxide (10ml) in all the tubes.
Ionic compounds, when in the solid state, can be described as ionic lattices whose shapes are dictated by the need to place oppositely charged ions close to each other and similarly charged ions as far apart as possible. Though there is some structural diversity in ionic compounds, covalent compounds present us with a world of structural possibilities. From simple linear molecules like H2 to complex chains of atoms like butane (CH3CH2CH2CH3), covalent molecules can take on many shapes. To help decide which shape a polyatomic molecule might prefer we will use Valence Shell Electron Pair Repulsion theory (VSEPR). VSEPR states that electrons like to stay as far away from one another as possible to provide the lowest energy (i.e. most stable) structure for any bonding arrangement. In this way, VSEPR is a powerful tool for predicting the geometries of covalent molecules.