Freezing Point Of Naphthalene :: essays research papers

Freezing Point of NaphthaleneI.PurposeTo determine the freezing phase of a k instantaneouslyn substance, naphthaleneII.Materialsringstand vaunt source rill tube riddle tube clampsthermometer naphthalene bunsen burner goggleshosestopwatchIII.Procedure1. suffer the Bunsen burner, attaching one end of the hose to theburner and theother to a gas source.2.Assemble the ring stand so that a ring clamp is attached to thestand holding the runnel tube that will be utilise in the experiment.3.Fill the test tube to approximately 1/8 capacity withnaphthalene crystals.4. Place the thermometer in the crystals so that it is surroundedby the naphthalenepowder but not touching the sides or bottom of the test tube.Use a clamp to holdthe thermometer in place.5. Ignite the Bunsen burner and using direct heat melt thenaphthalene powder untilit completely turns to a liquid. When the temperature reachesapproximately 90oCelsius, stop heating.6.Observe the change in temperature from 90o to 70o Celsius,rec ording thetemperature at regular intervals, preferably 15 seconds. Thisdata will be used tomake a chart later.7.Once the temperature has fallen to 70o, melt the naphthalenewhich is nowfrozen to remove the thermometer. Properly dispose ofthe naphthalene liquid asinstructed by the teacher.IV.DataTime ElapsedTemperature of NaphthaleneTimeTemperatureInitial (000)100oC70078.5oC03097.5oC71578.3oC10093.0oC73078.3oC13089.5oC74579.0oC20086.1oC80079.0oC23084.6oC81579.0oC24582.3oC83079.0oC30081.2oC84579.0oC31581.0oC90079.0oC33080.5oC91578.5oC34580.2oC93078.1oC40080.0oC94578.0oC41579.9oC100078.0oC43079.8oC101577.5oC44579.4oC103077.0oC50079.1oC104576.5oC51579.1oC110076.0oC53079.0oC111575.2oC54578.9oC113073.8oC60078.8oC114573.0oC62578.8oC120072.1oC63078.7oC121571.1oC64578.6oC123070.3oCV.graphical record(See following pages)VI.CalculationsUsing 80.1 oC as the theoretical value for the freezing layover ofnaphthalene, we can nowdetermine percent error.Percent illusion = ((Theoretical - Experimenta l) / Theoretical) x 100Percent Error = ((80.1 oC - 79.0 oC) / 80.1oC) x 100Percent Error = 1.4%VII.ConclusionsIn this lab, we heated the known substance naphthalene in a test tube toapproximately 100oC and observed its temperature while it cooled toapproximately 70oC. Over a time period of 12 minutes and 30 seconds, we recordedthe temperature at regular 15 second intervals, and, with this data, constructeda chart showing the prevalent curve. Upon inspection of the graph and our datachart, we found the experimental freezing lay of naphthalene to be around 79oC.