The purpose of the experiment Essays

The purpose of the experiment Essays The purpose of the experiment Essay The purpose of the experiment Essay In this experiment is to oxidize ethanol and then to test the product to determine whether it has been oxidized to ethanol or oxidized to ethanoic acid. The request of the experiment During the experiment, you will need to record all your observations clearly in an appropriate format. Record these appropriately in the space below. You should also consider the hazards associated with the materials and techniques used within the experiment and record it. Introduction 2, 4-DNPH (2, 4 dinitrophenylhydrazine) à ¯Ã‚ ¿Ã‚ ½ a kind of indicator, colorless liquid. CH3CH2OH (ethanol) à ¯Ã‚ ¿Ã‚ ½it is a clear, colorless liquid with a characteristic, agreeable odor. (http://scifun.chem.wisc.edu/chemweek/ethanol/ethanol.html) Required Equation CH3CH2OH +[O] à ¯Ã‚ ¿Ã‚ ½ CH3CHO + H2O CH3CH2OH +2[O] à ¯Ã‚ ¿Ã‚ ½ CH3COOH + H2O Material 1. Solvent à ¯Ã‚ ¿Ã‚ ½The distilled water need about 15cmà ¯Ã‚ ¿Ã‚ ½(15ml). 2. Ethanol (CH3CH2OH) à ¯Ã‚ ¿Ã‚ ½It is used to influence the solution, which in the dropping funnel. 3. Concentrated sulphuric acid (H2SO4) à ¯Ã‚ ¿Ã‚ ½It could use to be dilute in the pear shaped flask with the distilled water. 4. Dichromate (Na2Cr2O7) à ¯Ã‚ ¿Ã‚ ½It could use to be diffluent in the pear shaped flask with the ethanol (H2SO4). Experimental equipment 1. Bunsen burnerà ¯Ã‚ ¿Ã‚ ½ for use to warm the solution in the pear shaped flask. 2. Dropping funnelà ¯Ã‚ ¿Ã‚ ½ pour the mixture that have into the dropping funnel in process1. 3. Pear shaped flask 4. Condenserà ¯Ã‚ ¿Ã‚ ½ cooling the produce make the gas distillate and collect in the small flask. 5. Linkerà ¯Ã‚ ¿Ã‚ ½ for linking the dropping funnel, pear shaped flask and condenser. 6. Stopper 7. à ¯Ã‚ ¿Ã‚ ½ its about 50ml (50cmà ¯Ã‚ ¿Ã‚ ½) for collect the produce of reflux. Experimental process 1. Make up a solution containing 5g of sodium dichromate in 5cmà ¯Ã‚ ¿Ã‚ ½of water, add 4cmà ¯Ã‚ ¿Ã‚ ½of ethanol and pour the mixture into the dropping funnel. 2. Warm the acid in the pear shaped flask until it is almost boiling and turn off the Bunsen burner. 3. Carefully remove the stopper and put the dropping funnel in position, as shown in the diagram. 4. Add the mixture containing the ethanol at such a rate as to maintain the boiling of the mixture in the pear shaped flask .Collect the distillate and write down all observations in the space below. 5. Carry out the following tests on the distillate and record your observations. And the picture is shows how to setting up the equipment for this experiment was in the top. Safety In this experiment there is some hazard of the chemicals used in the experiment. Hazard in this experiment: 1. Before start the experiment, ensure that all of the glass joints are greased. Keep the experiment is safety. 2. In the step1, make sure the order for put the material. Because used the water to dilute the concentrated sulphuric acid (H2SO4). It can set free a large number of calorific capacities. So in that time is dangerous if you not careful to be scalded. 3. When used the Bunsen burner warm the acid. Make sure dont touch the equipment. Because is hot in that time. Suggest and justify improvement to the hazard in this experiment: 1. Before the experiment. Ensure that all of the glass joints are greased. 2. Remember the order to put the material in to the pear shaped flask. 3. When used the Bunsen burner warm the acid. Keep not very near of it. Observations 1. Make up a solution containing 5g of sodium dichromate in 5cmà ¯Ã‚ ¿Ã‚ ½of water, add 4cmà ¯Ã‚ ¿Ã‚ ½of ethanol and pour the mixture into the dropping funnel. à ¯Ã‚ ¿Ã‚ ½the Na2Cr2O7 is orange ,so the solution in this procedure is orange. 2. Warm the acid in the pear shaped flask until it is almost boiling and turn off the Bunsen burner. à ¯Ã‚ ¿Ã‚ ½the is H2SO4 colourless, so when it has been dilute is also colourless. 3. Carefully remove the stopper and put the dropping funnel in position, as shown in the diagram. 4. Add the mixture containing the ethanol at such a rate as to maintain the boiling of the mixture in the pear shaped flask. Collect the distillate and write down all observations in the space below. à ¯Ã‚ ¿Ã‚ ½the liquid change the colour to the dark green in this step. And there is a kind of smell comes out, it seems like the pear. 5. Carry out the following tests on the distillate and record your observations. à ¯Ã‚ ¿Ã‚ ½the product which been collected is colourless liquid. Used the material, which have been collect in this reaction. 1. Test for the presence of a carbonyl group to find out whether ethanal had been formed. -Put 5 cmà ¯Ã‚ ¿Ã‚ ½ of 2-4,initrophenylhydrazine in a test tube and cautiously adds 5 drops of the distillate. à ¯Ã‚ ¿Ã‚ ½In the text tube the solution is change the colour from the colourless to the yellow and there is also has the yellow precipitate has been product in the same time. 2. Text for the presence of an acid group to find out whether ethanoic acid had been formed. -Put 2 drops of the distillate in a test tube and used the PH paper to test. à ¯Ã‚ ¿Ã‚ ½the PH paper is change the normal color yellow not very much ,because it is only change a bit dark of the colour ,is likely a kind of dark yellow. And then check the PH value is about 4 or 5. Conclusion Use the results to decide whether an aldehyde or a carboxylic acid has been formed during this experiment. à ¯Ã‚ ¿Ã‚ ½in this experiment the most has been formed is the aldehyde and also has a little carboxylic acid. References Ethanol Ethanol is a clear, colorless liquid with a characteristic, agreeable odor. In dilute aqueous solution, it has a somewhat sweet flavor, but in more concentrated solutions it has a burning taste. Ethanol, CH3CH2OH, is an alcohol, a group of chemical compounds whose molecules contain a hydroxyl group, -OH, bonded to a carbon atom. The word alcohol derives from Arabic al-kuhul, which denotes a fine powder of antimony produced by distilling antimony and used as an eye makeup. Alcohol originally referred to any fine powder, but medieval alchemists later applied the term to the refined products of distillation, and this led to the current usage. Ethanol melts at -114.1à ¯Ã‚ ¿Ã‚ ½C, boils at 78.5à ¯Ã‚ ¿Ã‚ ½C, and has a density of 0.789 g/ml at 20à ¯Ã‚ ¿Ã‚ ½C. Its low freezing point has made it useful as the fluid in thermometers for temperatures below -40à ¯Ã‚ ¿Ã‚ ½C, the freezing point of mercury, and for other low-temperature purposes, such as for antifreeze in automobile radiators