...Determination of Boiling Points and Melting Points of Organic Compounds During this laboratory session, we will practice determining the boiling point of a liquid organic compound and the melting point (or we could call it the freezing point) of a solid organic compound. The boiling point of a liquid is the temperature at which the pressure of the vapor above a liquid equals the existing pressure. As we heat a liquid, the pressure of the vapor above the liquid slowly increases. When this pressure equals the pressure existing in the container, the liquid begins to boil– the liquid turns to vapor. If not contained, the vapor will “escape” into the atmosphere. In other words, the liquid evaporates. If the vapor is contained, and then passed through an area where the temperature is lower, the vapor will “condense” and enter the liquid state again. This would be a distillation. Atmospheric pressure is approximately 760 mm Hg; i.e., the weight of a column of mercury measuring 1 mm2 and 760 mm tall. This equates to about 29.7 inches of mercury. If we reduce the pressure above the sample that we are heating, we can reduce the boiling point of the liquid. This is referred to as a vacuum distillation or carrying out a distillation in vacuo. For example, while water boils at 100oC (or 212° F) at 760 mm Hg, it boils around 22oC at 20 mm Hg. The boiling point of a liquid is a physical characteristic of a compound. Many factors go into the estimation of the boiling point of a liquid such as...
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...Determination of Boiling Points and Melting Points of Organic Compounds During this laboratory session, we will practice determining the boiling point of a liquid organic compound and the melting point (or we could call it the freezing point) of a solid organic compound. The boiling point of a liquid is the temperature at which the pressure of the vapor above a liquid equals the existing pressure. As we heat a liquid, the pressure of the vapor above the liquid slowly increases. When this pressure equals the pressure existing in the container, the liquid begins to boil– the liquid turns to vapor. If not contained, the vapor will “escape” into the atmosphere. In other words, the liquid evaporates. If the vapor is contained, and then passed through an area where the temperature is lower, the vapor will “condense” and enter the liquid state again. This would be a distillation. Atmospheric pressure is approximately 760 mm Hg; i.e., the weight of a column of mercury measuring 1 mm2 and 760 mm tall. This equates to about 29.7 inches of mercury. If we reduce the pressure above the sample that we are heating, we can reduce the boiling point of the liquid. This is referred to as a vacuum distillation or carrying out a distillation in vacuo. For example, while water boils at 100oC (or 212° F) at 760 mm Hg, it boils around 22oC at 20 mm Hg. The boiling point of a liquid is a physical characteristic of a compound. Many factors go into the estimation of the boiling point of a liquid such as...
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...Melting Point and Boiling Point of Organic Compounds Miranda, Marilyn1, Salen, Vladimir, A.2 1Miranda, Marilyn, School of Chemical Engineering, Chemistry and Biotechnology, Mapua Institute of Technology; 2Salen, Vladimir A., CHM142L/B22, School of Chemical Engineering, Chemistry and Biotechnology, Mapua Institute of Technology [pic] ABSTRACT In this experiment, our attention will be focused on the effect of chemical structures of different organic compounds on two physical properties: their melting point and their boiling point. Melting point of compounds can be affected by intermolecular forces of attraction, geometric isomerism and purity. Boiling point of compounds can also be affected by intermolecular forces of attraction and by branching. The main purpose of this experiment is to (1)determine the effect of intermolecular forces of attraction and geometric isomerism on melting point of compounds, (2)determine the effect of purity on the melting point range of organic compounds and (3)determine the effect of intermolecular forces of attraction and branching on the boiling point of organic compounds. We can obtain wrong data as we encountered different errors while performing this experiment. As we go along to this laboratory report, we will able to know the effects of the different factors in melting point and boiling point of the compound and why the used compound arranged on that decreasing or increasing melting point or boiling point. Keywords: melting point...
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...Determination of boiling point and melting point of the organic liquids, in practice determining the boiling point of ethyl and Isopropyl Alcohol and the melting point of benzoic acid and Urea. However, the boiling point of a liquid is the temperature at which the pressure of the vapor above a liquid equals the existing pressure. As we heat a liquid, the pressure of the vapor above the liquid slowly increases. When this pressure equals the pressure presented in the container, the liquid begins to boil– the liquid turns to vapor. Many factors affect the boiling point and melting point of an organic compound, and one of which is the molecular structure. Purity and branching also affects the boiling and melting point of a compound. There are three trends that affect the boiling and melting points and one of these trends is the relative strength of the four intermolecular attractions is factor significally affects the boiling point and the melting point of a compound. INTRODUCTION Internationally, boiling points is a useful physical property for demonstrating the purity of an organic compound. Boiling point is the temperature at which the vapor pressure of a liquid equal atmospheric pressure or some other applied pressure. A boiling point is commonly measured when the liquid heated. The boiling temperature is measured as distillation vapor covers the bulb of a thermometer suspended above the boiling liquid. Typically, the most accurate boiling point measurement is the...
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...Determination of boiling point and melting point of the organic liquids, in practice determining the boiling point of ethyl and Isopropyl Alcohol and the melting point of benzoic acid and Urea. However, the boiling point of a liquid is the temperature at which the pressure of the vapor above a liquid equals the existing pressure. As we heat a liquid, the pressure of the vapor above the liquid slowly increases. When this pressure equals the pressure presented in the container, the liquid begins to boil– the liquid turns to vapor. Many factors affect the boiling point and melting point of an organic compound, and one of which is the molecular structure. Purity and branching also affects the boiling and melting point of a compound. There are three trends that affect the boiling and melting points and one of these trends is the relative strength of the four intermolecular attractions is factor significally affects the boiling point and the melting point of a compound. INTRODUCTION Internationally, boiling points is a useful physical property for demonstrating the purity of an organic compound. Boiling point is the temperature at which the vapor pressure of a liquid equal atmospheric pressure or some other applied pressure. A boiling point is commonly measured when the liquid heated. The boiling temperature is measured as distillation vapor covers the bulb of a thermometer suspended above the boiling liquid. Typically, the most accurate boiling point measurement is the...
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...Purity of a substance report Create a report describing the factors that influence the purity of a substance. It is important that chemical substances are as pure as possible. This reduces the chances of unnecessary side-effects and helps ensure an accurate dose in each tablet/substance. The purity of a substance or compound can be established by using data from its melting point or boiling point and from thin layer chromatography. Impure compounds have a range of melting and boiling points, as different substances contain different things they will have different boiling 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...
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...CHEMICAL BONDS Chemical Bonds I. Introduction Chemical compounds are formed by the joining of two or more atoms. A stable compound occurs when the total energy of the combination has lower energy than the separated atoms. The bound state implies a net attractive force between the atoms called a chemical bond. The two extreme cases of chemical bonds are the covalent bonds and ionic bonds. Covalent bonds are bonds in which one or more pairs of electrons are shared by two atoms. Covalent bonds, in which the sharing of the electron pair is unequal, with the electrons spending more time around the more non-metallic atom, are called polar covalent bonds. In such a bond there is a charge separation with one atom being slightly more positive and the other more negative, i.e., the bond will produce a dipole moment. On the other hand, Ionic bonds are bonds in which one or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other. In the extreme case where one or more atoms lose electrons and other atoms gain them in order to produce a noble gas electron configuration, the bond is called an ionic bond. Covalent bonding is a form of chemical bonding between two non-metallic atoms which is characterized by the sharing of pairs of electrons between atoms and other covalent bonds. Ionic bond, also known as electrovalent bond is a type of bond formed from the electrostatic attraction between oppositely charged...
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...TITLE OF EXPERIMENT: EXTRACTION WITH ACID AND ALKALINE OBJECTIVES: 1) Performed on acid-alkaline extraction 2) Learned to recovered benzoic acid and p-dichlorobenzene from its mixture using acid-alkaline extraction method 3) Determine the percent recovery of benzoic acid and p-dichlorobenzene 4) Determine the melting point of recovered benzoic acid and p-dichlorobenzene INTRODUCTION: Extraction involves dissolving a compound or compounds either from a solid into a liqiud or from a solution into another liquid. An acid-alkaline extraction is also known as a form of liquid-liquid extraction. Extraction is a procedure to separate compounds based on their relative solubility in two different immiscible solutions. Two layers are formed when the mixture are separated. The upper layer contains a low dense solvent. Basically in most of the extraction, one of the solvent used would be water as an aqueous solution and the other would be an organic solvent that is insoluble in water. The choice of organic solvent must be volatile so it can easily by removed by evaporation when forming crystals. The cleanest separations of organic compounds can be performed by using acid or alkaline solutions which can convert the compound to be extracted to a water-soluble and ether insoluble salt. Phenolic compounds undergo similar salt formation with sodium hydroxide solution. Hence, sodium hydroxide solution can be used to extract a carboxylic acid or phenolic compound from its solution...
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...The purpose of this experiment was for the student to be able to perform the dehydrobromination of meso-stilbene dibromide in order to produce an alkyne, diphenylacetalyene. The dehydrobromination of meso-stilbene dibromide requires removal of two hydrogen bromides—in other words, a double elimination. In order for the elimination of the halogen to happen, the hydrogen being attacked and the leaving group need to be on the same plane. More specifically, the molecule has to be in an anti-periplanar orientation in order to have the elimination reaction happen more efficiently. Even though a molecule in a syn-periplanar orientation also has the hydrogen and leaving group in the same plane, the fact that both groups are on the same side makes the molecule sterically hindered. The staggered conformation of the meso-stilbene dibromide is orbitally more favorable than the eclipsed conformation making the anti-periplanar orientation the more favorable orientation for an elimination reaction. Fortunately, the fact that meso-stilbene dibromide had a single bond allowed for this molecule to develop the anti-periplanar orientation by having rotated the bond until the hydrogen and the leaving group were on opposite sides of the molecule. When producing alkynes, there are two steps involved in the reaction: the formation of an intermediate alkene with a vinyl halide followed by the elimination of the halide to result in an alkyne. For the creation of the intermediate vicinal bromide in this...
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...oxides, all the outer electrons in the Period 3 element are being involved in the bonding - from just the one with sodium, to all seven of chlorine's outer electrons. The structures The trend in structure is from the metallic oxides containing giant structures of ions on the left of the period via a giant covalent oxide (silicon dioxide) in the middle to molecular oxides on the right. Melting and boiling points The giant structures (the metal oxides and silicon dioxide) will have high melting and boiling points because a lot of energy is needed to break the strong bonds (ionic or covalent) operating in three dimensions. The oxides of phosphorus, sulphur and chlorine consist of individual molecules - some small and simple; others polymeric. The attractive forces between these molecules will be van der Waals dispersion and dipole-dipole interactions. These vary in size depending on the size, shape and polarity of the various molecules - but will always be much weaker than the ionic or covalent bonds you need to break in a giant structure. These oxides tend to be gases, liquids or low melting point solids. Electrical conductivity None of these oxides has any free or mobile...
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...mouthwash makes up of 0.092% of this mixture. Eucalyptol is a liquid that has a 176.4 °C boiling point and 1.5 °C melting point. It is colorless and soluble in...
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...because their valence levels are full and normally noble gases do not add more electrons. Fluorine can have a high attraction to electrons that it attracts electrons from some noble gases and causes them to have a positive oxidation state. Only some reactivity is seen. Argon and xenon are the only ones to produce stable compounds. Neon has been wheedled into reactions under bead conditions of temperature and pressure. Helium has not shown an activity. Noble gases are nonpolar and that means they hold in the liquid and solid phases by van der Waals forces. Helium with the fewest electrons has the lowest boiling point. In this group, the boiling point increases from top to bottom. Helium was discovered by Janssen in 1868. Helium’s atomic number is 2. Its symbol is He. Also, it has a weight of 4.002602. Helium is a light, colorless gas. Helium has one of the lowest melting point. It’s the only liquid that cannot be made into a...
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...As you move down group 1 on the periodic table the atoms get more reactive. As you go down a group the atoms get bigger and bigger this makes it easier for atoms to lose their electrons. The metals react more vigorously with water as you go down the group. Lithium is at the top of the group and when it’s added with water its gets fizzy, floats and moves around the bowl as a gas is given off. When sodium is added with water it moves faster around the bowl, and it turns in to ball and a gas is given off. Potassium in the most reactive out of all the three as it’s below the other two metals. When potassium is added to water it gives off sparks and light on fire, potassium has a faster reaction. As you go down group 7 the atoms become less reactive....
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...Name: Mohit Mulani Experiment Due Date: 9/18/13 Section instructor: Dr. Thomas Kwok Section: 223 Recrystallization PURIFICATION AND CHARACTERIZATION OF ACETANILIDE Abstract This experiment dealt with 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 wit...
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