Thermochemistry an Ice Calorimeter Determination of Reaction Enthalpy Essay Example

Thermochemistry: an Ice Calorimeter Determination of Reaction Enthalpy Essay Thermochemistry: An Ice Calorimeter Determination of Reaction Enthalpy Heidi Moen Chemistry 151 Lab Section No. 47905 09/02/2010 Instructor: John Weide Abstract: In this experiment, an ice calorimeter was used to measure the energy transferred from a system to the surroundings in an isothermal heat transfer. By measuring the change in volume by milliliters before, during, and after a reaction of Sulfuric acid and Magnesium ribbon takes place in the calorimeter reaction test tube. Two trial experiments were preformed. The average of both trials was calculated to be -363. 7 kJ/mol, which is compared to the theoretical yield of enthalpy change; -464. 2 kJ/mol. Lab partner was John Grek. Results: Table 1 Change in volume in calorimeter after adding magnesium ribbon to Sulfuric acid Time (seconds) Milliliters 0| 0. 79| 60| 0. 73| 120| 0. 57| 180| 0. 46| 240| 0. 39| 300| 0. 345| 360| 0. 315| 420| 0. 299| 480| 0. 28| 540| 0. 27| 600| 0. 265| 660| 0. 26| Table 1 Change in volume in calorimeter after adding magnesium ribbon to Sulfuric acid Time (seconds) Milliliters | 0. 87| 60| 0. 84| 120| 0. 829| 180| 0. 82| 300| 0. 72| 360| 0. 635| 420| 0. 51| 540| 0. 43| 630| 0. 37| 690| 0. 33| 750| 0. 315| 840| 0. 28| 930990 | 0. 270. 26| Sample Calculations Calculations are given for the first addition of magnesium ribbon to H2SO4 0. 82 ml – 0. 32 ml x g/0. 0911 ml x 333 J/g x 1/0. 0049 x kJ/1000J = -372. 99 kJ/mol With the same calculations the result of the second addition of magnesium ribbon to H2SO4 are given -354. 34 kJ/mol Figure 1. Graph of change in volume in calorimeter after adding magnesium ribbon to Sulfuric acid Figure 2. Graph of change in volume in calorimeter after adding magnesium ribbon to Sulfuric acid Discussion After averaging both trials the results are shown to be -363. 67 kJ/mol, which is compared to the theoretical yield of enthalpy change; -464. 2 kJ/mol. The % error is -363. 67/-464. 2100 = 78. 34% Conclusion With getting an average ? H of -363. 67 kJ/mol with a 78. 34% yield, the results where unsatisfactory. If having to repeat the experiment, more precise measuring and recording would take place for a more accurate result. GENERAL INSTRUCTIONS We will write a custom essay sample on Thermochemistry: an Ice Calorimeter Determination of Reaction Enthalpy specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Thermochemistry: an Ice Calorimeter Determination of Reaction Enthalpy specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Thermochemistry: an Ice Calorimeter Determination of Reaction Enthalpy specifically for you FOR ONLY $16.38 $13.9/page Hire Writer The report must be typewritten (or use a word processor) and should not be written in the first person. Each page should have a 1 border on all four sides of the page. A page number should appear either in the upper right hand corner (or the bottom center) of each page except the first page of the report. The report should contain each of the following: I. Title Page II. Purpose of the Experiment: This should be a brief statement explaining why the experiment was conducted. (Abstract)Be sure to include names of lab partners and unknown numbers. Or you will lose points. III. Procedure: A very brief outline of the procedure(s) you used along with a list of any special equipment should be given here. IV. Drawing of Equipment (this is rarely used): A labeled drawing of any specialized equipment setups should be presented here. If you do a drawing, it should look GOOD. A digital photograph is an acceptable substitute. Cameras are available in the stockroom. V. Table of Data and Results: Data and results should be presented in a neat tabular form (must be typed). All Tables should be labeled. All the data should have units. VI. Calculations: A. Any formulas used should be presented here. A complete setup with UNITS should be shown for each type of calculation. You may accomplish this using an ink pen. B. Graphs should be neat and utilize as much as possible of the whole page without compromising the scaling. Graph title should be an accurate description of what is being plotted. X and Y axes should be labeled to explain both the property plotted and its UNITS. SCALING should be in reasonable increments (i. e. 1, 2, 5, 10 etc. ). For experiments that use the slope, the slope should be printed on the graph. VII. Questions and Answers: Any questions asked in the lab should be answered here in complete sentences. VIII. Discussion amp; Conclusion: In this section, the experiment and the results obtained are discussed that results in a conclusion of what was learned. The conclusion should directly address the purpose of the experiment. Also any problems encountered in the experimentation are stated along with any suggestions for improvement of the experiment. IX. Sign and Date your report. Or you will lose points. X. Appendices: Turn in your carbon copy of your data amp; report sheet as an appendix. Or you will lose points.

Sample of Objective Essay - An Effective Method to Present Your Life Goals

Sample of Objective Essay - An Effective Method to Present Your Life GoalsThe concept of an objective essay seems simple enough. If you were able to clearly explain the reason for your choice, the importance of your career objective and why you believe it is the most important thing you will ever do in your life, then the focus of your essay can be applied to any decision that may be made about your future. After all, it is only by developing a strong understanding of yourself and your prospective employer or organization that you will be in a position to make informed decisions.But with this simple form of essay, you are creating a separate document for every argument you make. As if this is not enough, you are then applying this essay to numerous applicants for similar positions. All of these things are bound to create a very difficult job on your part. It is not at all impossible to write an objective essay that presents your personal perspective and a compelling reason for your j ob objective in a positive light.Well, you don't have to do anything particularly difficult. As a general rule, if you were able to articulate the reasons for doing something you have done, then that means you have the ability to express your thoughts in a positive light.The best possible approach would be to try and consider a great example from a story from history. You can find numerous examples online, though you might not know which examples are truly effective. You can easily find a great example by simply searching the internet for 'emotional essay'. Here is one you can read:'One day, when I was fifteen years old, I was sitting on the patio outside my home, playing with my dog, when a strange man walked up to me. He was wearing a white lab coat, was clean shaven, and had his hands full of money. 'Hello, what brings you here?' he asked.I was surprised at the question and told him I was a college student. The man laughed. He said he thought that my parents were looking for a bo y to be the president of his company. He said he was a friend of his father and was about to start a new career for him.I began to cry and tell him I did not want to do this. He thought I was angry because I had been so upset when he tried to get in touch with my parents. When I told him how I felt, he told me he would come back in the morning and he would tell them why I had not gotten in touch with them and why he had chosen me to work for him.'