What is the direction of the acceleration of a projectile on an inclined planeHow can you show that the vertical component of projectile motion on an inclined plane is independent of the horizontal componentThe projectile motions constant downward acceleration is due to gravity. Since the force of gravity is vertical and there is no force acting on the puck horizontally the vertical acceleration and the horizontal velocity should be constant and independent
Determining Percentage Yield in a Chemical ReactionDerek Sue-Chue-Lam, Thaddaeus Kwan, Aaron YeQuestionWhat mass of copper is formed when excess aluminum is reacted with a given mass of copper(II) chloride dehydrate?PredictionThe theoretical yield for this experiment will be 0.744g.MaterialsEye protection ForcepsAluminum foil, 8cm x 8cm Hot plateCopper(II) chloride dehydrate, 2.00g Ring standTwo 150-mL beakers Iron ring50-mL graduated cylinder Wire gauzeStirring rod Watch glassRuler Crucible tongsCentigram balanceProcedureA mass of 2.00g of the copper salt was measured, to 0.01g, and dissolved in 50mL of water in a beakerThe aluminum foil was folded lengthwise to make a strip 2cm x 8cm. The strip was coiled loosely to fit into the copper chloride solution in the beaker, making sure that the strip was entirely immersed.The beaker was heated gently on the hot plate for 5min or longer, until all of the blue colour in the solution had disappeared. The heating was continued gently for another 5min.The forceps was used to shake loose all copper formed on the aluminum foil. The copper to a weighed beaker and rinse the copper with water was transferred carefully.The rinse water was poured off. The copper on the bottom of the beaker was spread.The beaker containing the wet copper was covered with a watch glass and the beaker was heated to drive off the water.When the copper was dry, the mass of the copper was determined.Observations:Mass of the beaker: 51.502 gMass of the beaker with copper(II) chloride dihydrate: 53.497 gMass of the copper(II) chloride dihydrate: 1.995 gMass of the beaker with copper: 52.400 gMass of the copper: 0.75 gAnalysis:The mass of the copper(II) chloride dihydrate was 1.995 grams instead of the wanted 2 grams.Theoretical yield of copper:Balanced Equation: 3CuCl2·2H2O(aq) + 2Al(s) 3Cu(s) + 2AlCl3(aq) + 6H2O(l)Molar mass of CuCl2·H2O: (63.55) + 2(35.45) + 2(2(1.01) + (16.00)) = 170.49 g/molMoles of CuCl2·H2O: 170.49 /1 = 1.995/xx = 0.0117 molMoles of Cu: 3CuCl2·H2O/ 3Cu = 1/1 = 0.0117/xx = 0.0117molMolar mass of Cu: 63.55 g/molMass/mol: 63.55/1 = x/0.0117x = 0.744 gActual yield: 0.75 gPercentage yield: 0.75/ 0.744= 101%The theoretical yield of copper for a reaction with 1.995 grams of copper (II) chloride dehydrate was calculated to 0.744 grams. However, the yield obtained in the experiment was 0.75 grams, giving a percentage yield of 101%.Procedure for calculating the theoretical yield: Determine the balanced equation of the reaction; calculate the amount of copper salt in moles; calculate the amount of copper metal in moles; convert the amount of copper in moles to mass in grams.Conclusion:In conclusion, the results from the experiment supported the prediction. It is possible to predict the amount of copper produced by the reaction because the balanced equation can be calculated and all of the elements’ molar masses are known. After calculating the amount of copper salt in moles, one can easily calculate the amount of copper metal in moles. Since the molar mass of copper is known, one can calculate the mass in grams of copper.Sources of error: There are a number of reasons why there may have been greater actual yield than theoretical yield. Firstly the reaction with the aluminum foil made the foil much thinner and therefore, easier to tear when the copper was being cleaned off. There are very high chances that a considerable amount of aluminum was concealed by the copper when it was being weighed. The heating of the copper after it was put into water may also have affected the weight measured since the copper darkened slightly which may have been an indication of the copper bonding to oxygen. Traces of water may also have been a cause for extra weight after having attempted to evaporate all the water out; some water may have condensed on the glass of the beaker and although the beaker was wiped out, a small amount may have remained unaccounted for.Applications:One of the most useful applications or chemistry is the synthesis of new substances that benefit society. New medicines are developed every year, and new materials for clothing, sports equipment, and cleaning products are advertised daily. That is why the discovery of new and better ways of synthesizing existing chemicals is so exciting. New procedures often follow the development of new technologies and always require an understanding of both qualitative and quantitative aspects of chemical reactions. Industries are particularly interested in the costs and efficiency of their chemical processes, and quantitative analysis is key to a company’s profitability. For example, it is important for manufacturers of a product to achieve as close to 100% yield as possible. The chemists or engineers must first determine the percentage yield of the operation and analyze all aspects of the process to look for ways of improving efficiency.
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[물리] Projectile Motion
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