Name: __________________________________ Teacher: ________________________________ DO NOT OPEN THE EXAMINATION PAPER UNTIL YOU ARE TOLD BY THE SUPERVISOR TO BEGIN Chemistry 2202 FINAL EXAMINATION June 2010 Value: 100% General Instructions This examination consists of two parts. Both parts are contained in this booklet and further general instructions are provided on appropriate pages. Part I – Multiple Choice (40%) Select the letter of the correct response from those provided. EITHER
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In this experiment‚ ethanol-wetted sawdust is dried using a vacuum tray dryer. This type of dryer is an example of an indirectly heated batch dryer (Geankoplis‚ 2003). In indirect-heat dryers‚ heat is transferred mostly by conduction‚ but heat transfer by radiation is significant when conducting surface temperatures exceed 150°C (Brown‚ 1973). There are two ways in describing the mechanism of drying of the ethanol-wetted sawdust. First is through the basis of ethanol content versus time and
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medicinal properties are. Lee‚ Park‚ and Yum (2012) studied the anti- oxidative properties of Taheebo. They used butanol and water to affect cell survival and tested the effect of Taheebo extract on these cells. The three serial extracts were selected for the study of regeneration on antioxidant enzyme activities because butanol and water extracts significantly affected cell survival. Treatment of hydrogen peroxide on the cells showed a dramatic repression
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highest percentage transmission. Beetroot was used for the experiment because it was easier to see the dye after the practical was completed. Putting beetroot cylinders into different boiling tubes‚ which contained three different standard solutions of Ethanol‚ they were left for half an hour at a certain temperature to get the dye out. Once the time was up‚ the solutions was added to cuvettes and inserted into the colorimeter to test how much light was passed through the sample. Preliminary Work:
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Chemistry – Heats of combustion. To determine the heats of combustion of selected alkanols and to use this information to determine the heat of combustion for a longer chain alkanols. Formula ΔH=-mCΔT Heat of combustion ΔH/n = molar heat of combustion. Materials -100 degrees thermometer -glass stirring rod -aluminium beaker -electronic balance -bosshead and clamp -retort stand Method 1) Set up the apparatus as shown above. 2) Measure the weight of aluminium can 3) Use the
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Fischer Esterification – nucleophilic substitution reaction Strong acid catalyst (concentrated sulfuric acid Purpose of a reflux is to heat a reaction mixture at its boiling temperature to form products‚ without losing any of the compounds in the reaction flask TO HAVE GREAT PERCENT YIELD: As reaction is reversible‚ removal of water or the addition of an excess of one of the reactants (cheaper one) drives the reaction towards formation of ester. (Excess carboxylic acid is used) Adding excess
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120.3 to 123.8 oC. Because it is lower than the known value‚ this means the obtain product is not completely pure. Impurities in the compound can result in a decrease in the compounds melting point‚ which is observed here. The impurities could be 1-propanol due to an insufficient drying. If the experiment was performed again‚ the product would need to be dried completely by properly running the suction filtration for a sufficient amount of time. The percent yield was 75.69%. This is somewhat low‚ and
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BALANCE We produce acetaldehyde by dehydrogenation of ethanol. Flow chart is as shown in the figure. Reaction: C2H5OH Catalyst: Æ CH3CHO + H2 Cu -Co-Cr2o3 Temperature: 280 – 3500 C. Process description: The raw material i.e.‚ ethanol is vaporized and the vapors‚ so generated‚ are heated in a heat exchanger to the reaction temperature by hot product stream. The product stream is cooled to –100 C and in doing it‚ all unreacted ethanol and acetaldehyde are condensed. The out going gaseous
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guajava) Peeling as a Potential Source of Ethanol ABSTRACT Apple guavas are abundant in the Phillipines and have been known for their high nutritional value and herbal properties. The peeling of the fruit Psidium guajava is known to contain a significant amount of glucose‚ a simple sugar which is essential in the fermentation process in ethanol making. The study was conducted to determine the effectiveness of apple guava peelings as a potential source of ethanol. The peelings underwent many processes
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list of alternative energy sources is Ethanol. Ethanol is a combustible substance that exists in small amounts in about one third of the gasoline sold in the United States. Many domestic vehicles have flex fuel engines that will run on gas that is up to eighty-five percent ethanol. The good thing about ethanol is that it can be refined out of products like corn or sugar. Because ethanol is a legitimate alternative to traditional fossil fuel‚ support for ethanol producers in the United States is very
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