...and melting temperatures. Sometimes the different substances may interfere with each other’s melting and boiling points. However the pure compounds have definite boiling and melting points. The presence of an impurity usually lowers the melting point and raises the boiling point. The greater the amount of an impurity, the bigger the differences from the true melting point and boiling point. Thin layer chromatography is similar to paper chromatography, but instead of paper, a thin layer of power is coated onto the plastic plate or glass. Different types of powders and solvents are used; this depends on the type of substance being separated. The results of a pure substance should show that the substance produces just one spot on the plate and the distance travelled by the substance is identical to known sample of that substance on the same plate. Weighing, mixing, heating, cooling, filtration, washing and drying are processes that can affect the yield and the purity of aspirin. In the chemical reaction, most of the time the aspirin produced might be impure. Therefore, aspirin must go through another process known as re-crystallization. Re-crystallization should be done many times till aspirin is free from impurities. Iron (III) chloride test can be done to check for impurities. Explain how...
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...I. Introduction: Food adulteration is a growing problem in Bangladesh as large numbers of consumers have become victims of consuming adulterated foods. This problem is becoming acute day by day. It is becoming essential to find out the reasons of food adulteration and how to solve this problem. Food and Agriculture Organization (FAO) has estimated that 45 million people in Bangladesh suffer from food poisoning or some kind of food-borne diseases round the year. Adulteration of food with toxic chemicals harmful to health has reached an epidemic proportion in Bangladesh. The newspapers have out and out conferred it, as the ‘silent killer’. It is now very difficult to find a sector of food industry which is free of adulteration. Experts believe that 76% of foods of our country are adulterated. Alarming increase of adulteration of food commodities create a strong public opinion for combating the ferocity of the offence. The study first identifies what is food adulteration and types of food adulteration. Secondly, the study aims to provide some suggestion for removing this problem. II. What is food Adulteration? Food Adulteration is the act of adding or mixing something harmful, useless and unnecessary substance to food. In other words, any food item may be considered as adulterated if its nature and quality are not up to the standard. As a result of adulteration, food or drink becomes impure and unfit for human consumption. Unscrupulous traders normally adulterate food....
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...Eating habits have been changing rapidly in modern India. While traditionally, Indian families used to cook food at home with healthy ingredients and knew what went into the meal, in modern times, with rising incomes and affluence, more and more people are moving away to readymade fast foods and eating regularly at restaurants. The food in many of these outlets is cooked with poor quality ingredients to attract and satisfy the palate rather than provide a wholesome nutritional meal. We now have a lot more varieties and the choices are many. Though, some of us may not be aware of the fact that the food we consume may be adulterated, 25 to 30 per cent of the food items in India are intentionally adulterated. Impure, unsafe Food adulteration is the addition or removal of any substances to or from food, so that the natural composition and quality is affected. Adulterated food is impure, unsafe and not wholesome. Food can be adulterated intentionally and accidentally. Unintentional adulteration is a result of ignorance or the lack of facilities to maintain food quality. This may be caused by spill over effect from pesticides and fertilisers. Inappropriate food handling and packaging methods can also result in adulteration. Intentional food adulteration is usually done for financial gain. The most common form of intentional adulteration is colour adulteration. Some examples of intentional adulteration are addition of water to liquid milk, extraneous matter to ground spices...
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...Part I The Beech-Nut case is primarily a case testing the behavioral ethics and decision processes of key stakeholders in the crisis. This case primarily gives an overview on different roles of the key players and their outlook toward the adulteration speculation. I would like to briefly introduce the key characters, their responsibilities, and issues faced by them in their communication strategy, all of which in the wake of the crisis formed a basis for a crucial decision-making by the CEO. Peter Anderson Role: President and CEO Responsibilities: As the newly appointed CEO of Beech-Nut Nutrition Corporation Anderson was responsible for the following * Turning the loss making Beech-Nut into a profitable company * Increasing the market share of Beech-Nut * To supply healthy products rich in nutrition in the market which met Nestlé’s product standards * To undertake changes in the operational and marketing activities of the company which directly influenced the profitability of the company Ethical issues those faced by Anderson while addressing his role are listed as follows * The most important dilemma Anderson was facing during the speculative adulteration crisis situation was whether Beech-Nut Corp needs to join PAI in a lawsuit against Universal Juice Company who were the suppliers of apple juice concentrate to Beech-Nut * Whether Beech-Nut needed to continue selling its apple juice products from the finished inventory which was around 700,000 cases...
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...Eating habits have been changing rapidly in modern India. While traditionally, Indian families used to cook food at home with healthy ingredients and knew what went into the meal, in modern times, with rising incomes and affluence, more and more people are moving away to readymade fast foods and eating regularly at restaurants. The food in many of these outlets is cooked with poor quality ingredients to attract and satisfy the palate rather than provide a wholesome nutritional meal. We now have a lot more varieties and the choices are many. Though, some of us may not be aware of the fact that the food we consume may be adulterated, 25 to 30 per cent of the food items in India are intentionally adulterated. Impure, unsafe Food adulteration is the addition or removal of any substances to or from food, so that the natural composition and quality is affected. Adulterated food is impure, unsafe and not wholesome. Food can be adulterated intentionally and accidentally. Unintentional adulteration is a result of ignorance or the lack of facilities to maintain food quality. This may be caused by spill over effect from pesticides and fertilisers. Inappropriate food handling and packaging methods can also result in adulteration. Intentional food adulteration is usually done for financial gain. The most common form of intentional adulteration is colour adulteration. Some examples of intentional adulteration are addition of water to liquid milk, extraneous matter to ground spices...
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...Physics Lab 4 (design) Design Aim To measure the effect on the heat of fusion of ice with varying percentage impurities of NaCl crystals in the water. Apparatus Ice cubes Distilled water Sodium Chloride crystals Styrofoam cup Calorimeter Digital balance with uncertainty (±0.01 g) Clamps Freezer Digital thermometer with uncertainty (±0.1°C) Glass rod Glass dish Pipette (±0.01 cm3) Variables Manipulated variables: Amount of impurity added to the water The aim of the experiment was to find the effect that impurities have on the heat capacity of the solution. Therefore the amount of impurities added to the water was varied. The amount added was 0%, 10%, 20%. Responding variable: Heat of fusion of the ice cube Since the composition of the solution has changed so will the heat of fusion. This is what is going to be evaluated in the experiment. Controlled variable: Temperature of the room, amount of water taken, impurity used (NaCl) Method of controlling variables The temperature of room was kept constant. The amount of water taken was kept constant at 50 cc. The same impurity was used so that the composition of the impurity would remain the same. Method to control variables Procedure Fill the styrofoam cup with 50 cm3 of water and place it in the calorimeter. Measure the temperature of the he room temperature by dipping the thermometer in water. Place the glass dish on the digital balance and zero the digital balance (this step...
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...purification and analysis techniques like recrystallization, hot filtration and melting point measurement. Recrystallization and hot filtration use relative solubility of impurities and acetanilide (desired substance) to purify the crude form and melting point analysis is used along with weight measurement to examine the purity and quantity of yield. Introduction In the experiment, we used the hot filtration and recrystallization to separate pure acetanilide from its crude form. The purification of such chemicals is an especially important technique as it can be applied cheaply to medical drugs and remove the impurities in/on them which among other things increase toxicity (sideeffects) and reduce the efficiency of the drug. Other purification procedures such as extraction, sublimation and chromatography can also be used, but recrystallizing the resulting substance after these will yield a higher level of purity.The processes used rely upon the relative solubilities of the impurities in crude acetanilide with regards to each other and the pure form of the chemical. Hot Vacuum filtration – This process involves the filtering out of an insoluble substance (impurity or desired compound) that hasn't dissolved in the solvent at a high temperature. A vacuum is created by tubing between a sidearm flask and running water. Recrystallization ...
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...and light impurities from wheat, paddy ,corn and oil bearing materials. Rice Vibrating Cleaning Sieve is designed with doubledecked sieve, and good seal. It has much better effects especially for big impurities contained in grain. It is also used for granule separation in food and chemical industry. The Rice Vibrating Cleaning Sieve is driven by double vibratory motors , which enables the airtight sieve to keep a back-and-forth track of movement with different angles and amplitude . It can be used in the cleaning stages for grain warehouse , mills ,feed-grain process factory and oil factory to remove impurity and barnyard grass from paddy , wheat , corn and sunflower seeds , in addition , it can also be used in the grading of intermediary and final rice products . We can supply you with reasonable and competitive price and good quality TQLZ Series Rice Vibrating Cleaning Sieve. If you are interested in any of products, please contact us for more information. TQLZ series Rice Vibrating Cleaning Sieve is suitable for cleaning raw grain for grain processing plant and grain storage. The Rice Vibrating Cleaning Sieve of different specification can separate large, small and light impurities from wheat, paddy ,corn and oil bearing materials. Rice Vibrating Cleaning Sieve is designed with doubledecked sieve, and good seal. It has much better effects especially for big impurities contained...
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...are conveyed by elevators and 2 groups of aspiration systems are used to dedust. It includes 2 sifting processes to remove big and small impurities in the raw bean. Then the destoner fully removes the stones. The magnetic separator increases purity of the finished products to guarantee good taste by removing metal impurities so as to prevent them going into the final beans. 1. To protect bean cleaning machine to work normally by bean cleaning machine. Unprocessed grains always contain some hard impurities, such as stones and metal. In grain processing, the hard impurities may easily damage the bean cleaning machine, affect the technological effect and increase maintenance cost, or even cause fire disaster or dust explosion. Besides, if there has impurities with large volume, it may easily block the feeding port, make the feeding quantity reduce or uneven, reduce the technological effect of bean cleaning machine and affect processing performance. Sometimes, the soft impurities, such as rope， scraps of paper, may also easily twine or block the bean cleaning machine. If he dust in the unprocessed grains flies out, it will cause pollution and damage the production environment. To protect normal processing, we should clean these impurities by bean cleaning machine. 2. To ensure products quality by BEAN CLEANING MACHINE. If the grain impurities are not removed, they will be mixed into the end products and reduce end products purity. For example, if dust is...
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...Semiconductor Semiconductors :- Most of the solids can be placed in one of the two classes: Metals and insulators. Metals are those through which electric charge can easily flow, while insulators are those through which electric charge is difficult to flow. This distinction between the metals and the insulators can be explained on the basis of the number of free electrons in them. Metals have a large number of free electrons which act as charge carriers, while insulators have practically no free electrons. There are however, certain solids whose electrical conductivity is intermediate between metals and insulators. They are called ‘Semiconductors’. Carbon, silicon and germanium are examples of semi-conductors. In semiconductors the outer most electrons are neither so rigidly bound with the atom as in an insulator, nor so loosely bound as in metal. At absolute zero a semiconductor becomes an ideal insulator. semiconductors - Theory and Definition Semiconductors are the materials whose electrical conductivity lies in between metals and insulator. The energy band structure of the semiconductors is similar to the insulators but in their case, the size of the forbidden energy gap is much smaller than that of the insulator. In this class of crystals, the forbidden gap is of the order of about 1ev, and the two energy bands are distinctly separate with no overlapping. At absolute o0, no electron has any energy even to jump...
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...materials are the main element from which In the market today the vast majority of all solid state devices are fabricated. Semiconductor family of materials includes the elemental semiconductors Si and Ge, compound semiconductors such as GaAs and some alloys also includes in this list. Some of the major attributes of the present-day age (i.e., the age of electronics) are such common tools as computers and fibre-optic telecommunication systems, in which semiconductor materials provide vital components for various micro-electronic and optoelectronic devices in applications such as computing, memory storage, and communication. The reason why the semiconductor materials are so vastly used is that we can easily vary its characteristics by adding impurity content to it. The process is called doping. Semiconductor conductivity can be controlled by introduction of an electric field, by exposure to light, and even pressure and heat; And the semiconductor devices are the combination of p-type and n-type semiconductor material. P-n...
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...how to perform recrystallization technique in order to purify compounds and to apply TLC and melting point detection technique to test the purity of the recrystallized sample. In chemistry, recrystallization is the purification technique for solid compounds, using an appropriate solvent, to coax out either the desire compound or the impurities. The name “recrystallization” is given because of the crystals often formed when the experiment is successfully performed.2,3 Recrystallization works based on the difference in solubility when the temperature changes. Therefore, picking the solvent to dissolve the compound is a very tricky and important part. For single-solvent recrystallization, which is performed in this experiment, the chosen solvent should not dissolve the sample while cold, so that the crystal can be formed when the temperature drops. However, the solvent should dissolve the sample completely while hot in order to release all the impurity crystals being trapped up in the solid form of the desired compound. Furthermore, the impurities should have higher solubility than the desired compound in that chosen solvent, so that all the impurities would remain in the solution while recrystallization takes place.2,3 In case no single solvent can be found, a system of two solvents can also be used for recrystallization. Generally speaking, in this solvent pair, one of them can completely dissolve the sample while the other one cannot dissolve the sample at all. The primary requirement...
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... |1200 (approx.) |1500 (approx.) |More absorption capacity | |3 |Feel | |Less Soft |Soft |Softer feel keeps patient | | | | | | |more comfortable. | |4 |Chemical processing | |Done |Not required |No requirement of chemical | | |Sizing,de-sizing,scouring| | | |processing makes nonwoven | | |, bleaching | | | |fabric free of impurities. | | | | | | |Hence, the chances of | | | | | | |presence of any chemical | | | | | | |residue are eliminated. | |5 |Production area | |Atmospheric |Clean room environment |Clean room production | | |environment | | |...
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...CORN CLEANING MACHINE works like this: The materials go into the sieve for big impurities from work bin which is baffled to uniformly scatter the materials on the sieve.The sieve vibrates to separate the big impurities from the materials .The big impurities are discharged from the outlet. Corns,mediate and small impurities fall onto another sieve through holes. The small and flat corn vibrates with rubber ball to fall onto bottom plate through the holes and goes out from outlet.The other materials are graded according to their different gravities from the air suction system.The grains mixed with stones fall on the destoning sieve along the first,second and third grading devices.The destoning sieve seriously searches out stones and some impurities heavier than the corns and discharges them outside.The lighter impurities are discharged through air suction tunnel due to the reverse wind generated by destoning adjustment plate.The destoned materials flow to the end of sieve and go to the corn peeling machine. First, the enterprises should be familiar with corn cleaning machine power consumption. A workshop should be divided into several workshop departments or sub-processes. The electric quantity which these sub-processes demand can be decided accurately by the integer power measurement methods. Second, during corn cleaning machine energy consumption, power consumption is also a cooperation method for indicating production operation. Therefore, in corn cleaning machine operation...
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...recrystallization still remains one of the top methods in obtaining scalable amounts of ultra-pure organic materials. This technique essentially relies on the different solubility’s of compounds to be purified in a solvent. The impure material will thus dissolve in a hot solvent, allowing the removal of these impurities through filtration, which will then allow the desired compound to crystallize as it cools. Solvents and solubles are important factors in recrystallization; the substance should have a high solubility at elevated temperatures, and low solubility at low temperatures. Additionally, the solvent should have the capability of dissolving or not dissolving impurities, which will determine the occurrence of filtration. Compared to insoluble impurities, which are filtered once the compound dissolves in the hot solvent, soluble impurities are filtered out in solution as the compound is left behind. In some cases, decolorizing carbon may also be used to remove colored impurities. Also, it is important to effectively use the perfect amount of hot solvent to avoid dissolving much of the desired compound, which allows it to pass through the filter alongside the impurities. This solution is known as the mother liquor; the liquid that remains after filtration, containing significant amounts of the desired material. In certain...
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