9.1 Orbitals and Theories of Chemical Bonding 1. Which one of the statements concerning valence bond (VB) and molecular orbital (MO) bond theories is correct? a) MO theory predicts that electrons are localized between pairs of atoms. b) In VB theory‚ bonding electrons are delocalized over the molecule. c) MO theory accurately describes bonding in O2 and NO‚ VB theory does not. d) VB theory can describe molecular bonding in excited states. e) MO theory is used to accurately predict
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Ink Chromatography Lab Background Information Paper chromatography is an analytical method that is used for separating and identifying mixtures of substances into their smaller parts. Paper chromatography works because the ink used contains several dyes (pigments) that when place on porous paper are dissolved in a solvent by capillary action. When the pigments (solutes) are dissolved in the solvent (water & alcohol mixture) they move through the paper at different rates depending on their
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Abstract Finding the melting point of an organic substance is a practical and efficient way for scientists to identify an unknown substance or determine a known substance’s level of purity. When organic substances are mixed together in varying degrees they take on a melting characteristic that is lower and broader than in its pure form. This property was manipulated in the lab to observe the various melting points of Naphthalene and Biphenyl when the percentage of composition was altered. A
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Gas Chromatography Analysis of Product Mixtures Gas Chromatography Guidelines‚ Handout. Introduction Gas chromatography is a technique used to analyze chemical compounds that can be vaporized and separated in a gas phase column. Once separated‚ the analyzed substance is passed through a detector and data is obtained. The samples that we are going to analyze are: the EtOAc from Simple distillation‚ the Fraction 1‚ Fraction 2‚ and Fraction 3 from the Fractional Distillation. Experimental Procedure
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The purpose of this lab was to use gas chromatography to determine the relative amounts of the three components of gas products from the dehydration reaction of 1- and 2-Butanol with sulfuric acid and the dehydrobromination reaction of 1- and 2-Bromobutane with potassium tert-butoxide. E1 reactions are two-step unimolecular reactions. The first step of an E1 reaction occurs when a leaving group‚ which consists of a weak base‚ leaves an organic compound‚ leaving an intermediate carbocation. In the
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mobile phase can be liquid‚ gas‚ or supercritical fluid. How Does Chromatography Work? Chromatography is a surface effect. It works by first starting off with an unidentified liquid being injected into a column. As the chemicals in the liquid move down the column‚ they separate depending on their physical and chemical attributes‚ such as speed and weight. To easily picture the process‚ the example will pertain to a paper chromatography process in which the liquid is moving over the paper‚ separating
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foreground the composition‚ wearing a flowing white skirt and a corset of white straps that wrap around her shoulders and upper body. Kahlo’s breasts are exposed and the front of her upper body is bisected‚ revealing that “her spinal column is replaced by a broken Doric column.” In addition‚ several nails protrude from the skin on her face‚ arms‚ torso‚ and legs. In the background‚ a blue sky with white clouds hangs over the cracked‚ fissured landscape where Frida stands. Unlike The Two Fridas‚ this
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Chromatography is a laboratory technique for the separation of a mixture. The mixture is dissolved in a fluid called the mobile phase‚ which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at different speeds‚ causing them to separate. The separation is based on differential partitioning between the mobile and stationary phases. Subtle differences in a compound’s partition coefficient result in differential retention
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CHEM 3152-003 Experiment 2: Fractional Distillation and Gas Chromatography Introduction: The purpose of this experiment was to separate a mixture of ethyl acetate (EtOAc) and toluene by using the method of fractional distillation and to analyze the fractions using gas chromatography (GC). ethyl acetate toluene Distillation is a method known as separating or purifying a liquid or mixture by vaporization and condensation. In a simple distillation‚ the liquids being separated boil below 150 0C
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It was concluded that the product created was paracetamol when a thin layer chromatography test was performed and observed under ultraviolet light (which is discussed further down the page). An unknown substance was treated with acetic anhydrate and resulted with paracetamol. A compound that behaves in this matter is 4-aminophenol and is widespread in the industrial production of this drug. Upon these observations was the build up of “Chemical A” decided. When 4-aminophenol is t treated with
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