Positive reaction rate and time image of the thermal reaction
For the positive reaction rate and time diagram (V-t diagram) of the thermal reaction, there were the following characteristics: - If the temperature was changed, the reaction would absorb heat. According to Le Chatelier's principle, the equilibrium would move forward. The image showed that as time passed, the positive reaction rate increased at the moment of heating up (because the temperature increased, the molecular motion increased, the effective collision probability increased, and the reaction rate increased). Then, as the reaction progressed, the positive reaction rate gradually decreased until it reached a new equilibrium state, and the positive reaction rate under the new equilibrium was greater than before the temperature increased. - If it involved a change in pressure, for the heat absorption reaction with a change in the number of gas molecules before and after the reaction, if the pressure was increased, the reaction would move in the direction of the decrease in the number of gas molecules (if the positive reaction was the direction of the decrease in the number of gas molecules), the positive reaction rate would instantly increase, and then gradually decrease to a new equilibrium as the reaction progressed. The positive reaction rate under the new equilibrium was greater than that before the pressure was increased. If the pressure was reduced, the positive reaction rate would instantly decrease, and then gradually change to a new equilibrium as the reaction progressed. - If a catalyst was added, the positive reaction rate would instantly increase, and the time to reach equilibrium would be shortened, but the equilibrium would not move. In other words, the final positive reaction rate would stabilize at the same level as the original equilibrium (the catalyst would change the positive and reverse reaction rates to the same extent). Read more exciting novels for free
What is the reaction of the aluminum thermal reaction? Is it an exhalation reaction?
Aluminiothermic reaction was a kind of oxide-reduction reaction between aluminum and metal or non-metal compounds at high temperatures. Aluminiothermic reaction was an exhaling reaction, and its heat release was very large, usually enough to heat the product above the melting point, and the reaction could generally occur locally and be self-sustaining. This characteristic also reflected the energy-saving characteristics of the reaction. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
How to determine the positive and negative reaction rate of a chemical reaction
The positive or negative of the change in the temperature had no direct relationship with the reaction rate. ** I. Judgment of Positive and Negative EnChange ** 1. ** Based on the energy of the reagents and products ** - If the total energy of the reagent is higher than the total energy of the product, there will be energy release during the reaction, and the change in the heat is an exothermic reaction. For example, in a combustion reaction, when a flammable substance and oxygen react to form a product, the energy of the reaction is higher than the energy of the combustion product. The reaction releases heat, and the heat becomes negative. - When the total energy of the reagent is lower than the total energy of the product, the reaction needs to absorb energy to proceed. The change in the heat is an heat absorption reaction. For example, the reaction of water gas, carbon and water vapor reacted at high temperatures to form carbon dioxide and hydrogen. The reaction needed to absorb heat, and the heat would become positive. 2. ** From the perspective of chemical bonds ** - The essence of chemical reactions was the breaking of old chemical bonds and the formation of new chemical bonds. The breaking of chemical bonds absorbed energy, and the formation of chemical bonds released energy. If the energy absorbed by a bond breaking reaction is less than the energy released by the bond forming reaction, the reaction will be heat releasing and the change in the heat will occur. On the other hand, if the energy absorbed by the bond breaking reaction is greater than the energy released by the bond forming reaction, the reaction will be heat absorbing and the change in the heat will occur. For example, when hydrogen and oxygen react to form water, the energy absorbed by separating the chemical bonds in hydrogen and oxygen is less than the energy released by forming the hydrogen and oxygen bonds in water. Therefore, the reaction is an exothermic reaction, and the energetics become negative. ** 2. Judgment of reaction rate ** 1. ** Concentration of Reactants ** - Generally speaking, under the same conditions, the higher the concentration of the reagent, the more molecules of the reagent in the unit volume, the higher the probability of collision between molecules, and the faster the reaction rate. 2. ** Temperatures ** - When the temperature rises, the energy of the molecules increases, the speed of the molecules increases, and the frequency of effective collisions increases, thus accelerating the reaction rate. 3. ** Pressure (for reactions involving gases)** - When the pressure increased, the volume of the gas decreased, the concentration of the reagents increased, and the reaction rate increased. However, the effect of pressure on the reaction rate was essentially achieved by changing the concentration. 4. ** A catalyst ** - The catalyst could reduce the activation energy of the reaction, making it easier for the molecules to react, thus speeding up the reaction rate. There were also some kinds of catalyst that could slow down the reaction rate, but they were relatively rare. 5. ** Solid surface area (for reactions involving solid)** - The larger the surface area of the solid, the larger the area of contact with other reagents, and the faster the reaction rate. For example, when bulk and powdered solid react with other reagents, the reaction rate of the powdered solid is usually faster. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What are the problems with the positive reaction rate being greater than the reverse reaction rate?
The reason why the positive reaction rate was greater than the reverse reaction rate was as follows: 1. ** Concentration Effect ** - When the concentration of the reagent increased, according to the collision theory, the effective collision frequency between the molecules of the reagent increased, and the positive reaction rate instantly increased. At this time, the concentration of the product had not changed, and the reverse reaction rate did not change. Therefore, the positive reaction rate was greater than the reverse reaction rate, and the reaction went forward. For example, in the reaction A + B, if the concentration of A or B increases, the positive reaction rate will increase before the reverse reaction rate. - When the concentration of the product was reduced, the reverse reaction rate would decrease. However, the positive reaction rate would not change when the concentration of the reagent remained unchanged. This would also cause the positive reaction rate to be greater than the reverse reaction rate, causing the reaction to move forward. 2. ** Effect of temperature (targeted at the heat reaction)** - For example, when the temperature was raised, the positive and reverse reaction rates increased. However, since the positive reaction was a thermal reaction, according to Le Chatelier's principle, the increase in temperature was not conducive to the progress of the thermal reaction, so the increase in the reverse reaction rate was greater than the increase in the positive reaction rate. Then, for a reaction that was a positive reaction, when the temperature was raised, the increase in the positive reaction rate was greater than the increase in the reverse reaction rate. The positive reaction rate was greater than the reverse reaction rate, and the reaction was positive. 3. ** Pressure effect (for reactions where the gas volume changes before and after the reaction)** - For example, for the reaction, the total volume of the gas before the reaction (1 + 3 = 4) is greater than the total volume of the gas after the reaction (2). When the pressure increases, according to the ideal gas state equation,[pV = nRT]([p] is the pressure,[V] is the volume,[n] is the amount of matter,[R] is the constant,[T] is the temperature), the gas concentration increases, and the positive and reverse reaction rates increase. However, because the reaction moved in the direction of decreasing the volume of the gas, the increase in the positive reaction rate was greater than the increase in the reverse reaction rate. The positive reaction rate was greater than the reverse reaction rate, and the reaction proceeded in the positive direction. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The thermal reaction temperature of iron
The temperature of iron reaching the red hot state was about 500 - 1200 ° C. As the temperature increased, it would appear dark red, bright red, orange and other colors. The melting point of iron was 1538 ° C. If the temperature continued to rise to 1700 ° C, it would reach the incandescent state. In addition, in the thermit reaction, the aluminum powder and iron dioxide powder were mixed in a certain proportion and then ignited to produce a high temperature to melt the iron. The reaction temperature could reach 3000 ° C, and the temperature of the molten iron could reach more than 2500 ° C. Different types of iron have different melting temperatures. For example, tinplate (malleable iron) has a melting temperature of 1320 - 1350°C, gray cast iron has a melting temperature of 1320 - 1350°C, and spherical cast iron has a melting temperature of 1340 - 1400°C. The melting temperature of steel varies according to its carbon content. The melting temperature of low carbon steel is 1420 - 1450°C, medium carbon steel is 1450 - 1470°C, high carbon steel is 1470 - 1500°C, and alloy steel is 1450 - 1570°C. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The Determination of Reaction Rate and Reaction Constant
The chemical reaction rate represented the speed of the chemical reaction, which was the rate of change of the reaction progress with time or the reaction progress of the chemical reaction in unit time and unit volume. The average reaction rate was the decrease of the concentration of the reagent or the increase of the concentration of the product in unit time. The instantaneous reaction rate was the limit of the average reaction rate that approached zero. The reaction rate constant represented the chemical reaction rate at a unit concentration. It was independent of the concentration, but it was affected by factors such as temperature, catalyst, and solid surface properties. Usually, the larger the reaction rate constant, the faster the reaction would proceed. There were two common methods to measure chemical reaction rates: chemical and physical methods. The chemical method used chemical analysis to directly measure the change in the concentration of the reagent or product over time to obtain the chemical reaction speed. However, the chemical analysis speed might not be able to keep up with the reaction speed and affect the measurement results. However, it could provide an absolute concentration value. The physical method was more extensive and convenient. It was to determine the reaction speed based on some physical properties that changed with the reaction, such as the pressure method, the distension meter method, or the volume method; the optical rotatory method, the interference method, the chromicity method, and the spectrophotosity method; and the electrical property method, such as the conductivity method, the potential method, the polarography method, the dielectrical constant method, and the mass spectrum method. As for the determination of the reaction constant, for example, in the experiment of determining the rate constant of the fading reaction by the method of the catalyst, based on the principle of the catalyst kinetic method, the reaction system of the fading reaction of the Evans Blue by the reaction of the potassium bromate under the action of the NaNO3 was proposed. The corresponding chemical reaction rate constant was calculated by measuring the change of the absorption of the reaction system at different initial concentration and temperature. In terms of specific operations, the stock solution of the relevant reagents was first prepared, and then the reagents were added into the color-measuring tube according to a certain order and dosage. The timing and volume were started, and then the absorption curve was measured. The reaction constant was determined by preparing reaction solutions of different compositions, adding the solution after reacting for a period of time to stop the reaction, and taking a sample to measure the absorption curve. Finally, the concentration of other components was maintained at a constant temperature, and the change of the light absorption with time when different amounts of the solution of bromate or the solution of NaNO3 were measured, as well as the change of the light absorption with time when the specific amount of the solution of NaNO3 was measured at different temperatures. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Dismountable reaction kettle thermal jacket
The following features of the thermal jacket are shown: 1. ** Construction and production **: Usually made of high and low temperature resistant, fire-resistant and thermal insulation materials, including the inner lining, the middle insulation layer, and the outer protective layer. It was carefully designed and made according to the specific shape of the reactor, the environment, the three-dimensional drawings of the reactor, and the installation of the equipment on site. 2. ** Performance advantage ** - ** Heat insulation **: It is a reliable and effective heat insulation material. It can achieve greater heat insulation performance with a lower thickness. For example, it can meet the requirements of the temperature below 50 ° C (not higher than the ambient temperature by 15 ° C) after insulation. The thermal conductivity is 0.035W/m.K at room temperature. It effectively prevents heat from escaping from the inside of the reactor or external heat from entering the inside of the reactor to maintain the internal temperature of the reactor. - ** Adaptability and adaptation **: It fits the equipment better and has good flexibility. It can adapt to the heat insulation requirements of different reactors. It can be customized according to the size of the equipment and has a good fit with the equipment. - ** Durability **: High temperature resistance, anti-corrosion, material can withstand high tension, such as 3500N/50mm tension, waterproof, anti-oil, anti-corrosion and weathering, strong weather resistance (waterproof 3ds, fire resistance GB8624 -2012: B1 and anti-corrosion H2SO4) and other characteristics. - ** Others **: The thermal insulation cover is light, which can reduce the overall weight of the reactor. It also has a good sound-absorbing effect. It has a beautiful appearance and is environmental friendly. 3. ** Ease of Use ** - ** Easy to disassemble **: It is designed to be easy to install and disassemble (such as the Velcro and drawstring design). It can be reused. This is very convenient for equipment maintenance or operations such as removing the thermal suit to cool down. 4. ** Meaning of application **: The heat preservation of the reactor is very important. The reaction of the materials inside requires a certain temperature support. Heat is the core problem of the reactor. The disassembled thermal suit helped to prevent the heat source from affecting the quality of the product. It not only improved the reaction efficiency and effectively reduced the heat loss, but also fully utilized the waste heat or the heat generated after the reaction to save production costs. It was of great significance in the thermal insulation of chemical vessels such as large reactors and storage tanks. If the thermal insulation was not handled properly, the physical properties in the reactor would change greatly, affecting normal production. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
What are the factors that affect the thermal reaction?
The factors that affect the thermal reaction include: 1. Energy factors, such as the change in the reaction process, the change in the 2. The chaos factor of the system was known as entropies. Entropies could describe the degree of chaos or disorder of the system. The change in the entropies of a reaction could help predict the trend and spontaneous nature of the reaction. 3. For some specific reactions (such as the nitrogen and hydrogen reaction), temperature, pressure, the ratio of nitrogen and hydrogen, and the noble gas were influencing factors. 4. During the curing process, factors such as temperature, pressure, and the nature of the raw materials would affect the thermal process. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
First Order Reaction Formula of the Reaction Rate
The first-order reaction rate equation was: r = -dt/dt = kc, and its integral form was: Where, a is the concentration of the reagent at the beginning of the reaction, c is the concentration of the reagent at time t, and k is the rate constant. The unit is the negative power of the time unit, such as s^{-1}, min^{-1}, h^{-1}, d^{-1}, etc. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
Is the reaction rate the same for different reaction levels?
The reaction order was closely related to the reaction rate. Under normal circumstances, the reaction rate would be different depending on the reaction order. The reaction order reflected the relationship between the reaction rate and the concentration of the reagents. It was the sum of the powers of the concentration of the various reagents in the rate equation. Different reaction orders meant that the concentration of the reagents affected the reaction rate in different ways and degrees. For example, the reaction rate of a zero-order reaction had nothing to do with the concentration of the reagent, the reaction rate of a first-order reaction was proportional to the first power of the concentration of the reagent, and the reaction rate of a second-order reaction was proportional to the second power of the concentration of the reagent. However, the reaction rate was also affected by other factors, such as temperature, catalyst, etc. Under certain conditions, even if the reaction order was different, it was possible that other factors affected the reaction rate so that the reaction rate of different reactions was the same at a certain time. However, this was a special case and not the normal case. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>
The Reaction Rate of the Reaction of Keto and Bihydrogen Sulphite
In the addition reaction of the carbonyl-like group of the acid, the reaction rate was different. Propional reacted the fastest with bisulfuric acid, followed by Cyclohexuron, methylethyluron, and dibenzone. Among the alkahedes, the reaction rate of the addition of formalin to the nucleus was the fastest. Because the hydrogen atom attached to the carbonyl-group was the smallest, the steric hindrance was the smallest, so the reaction was the fastest. Aldes, fatty methyls, and cycloketones with less than eight carbon atoms could undergo an addition reaction with saturated water-based bisulphite solution (about 40%). The reaction rate of different alkyls and methyls was different, which was related to the atoms or groups connected to the carbonyls. The smaller the steric hindrance caused by the atoms or groups, the faster the reaction rate. <a href="/?from=ask_words" style="color:red" target="_blank">Read more exciting novels for free</a>