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Chemistry: Magnesium Experiment

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Submitted By shakaboomboom8P
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During the experiment we encountered various problems. While weighing the magnesium, some of the strips fell and other strips fell off, therefore we had to weigh it again. When we did the first reaction, the final temperature of the reaction rose to only about 65C due to the fan and air conditioning in the area that we were working in. We consulted with the instructor, and he told us that the final temperature had to be at least 70C. We moved to another area where the fan was not blowing directly at us, and we did the first reaction again, finally obtaining the desired temperature. The next problems we encountered were in the calculations of the enthalpy for the reaction: Mg(s) + 1/2O2(g)  MgO(s)
At first, we forgot to change the enthalpies from the reactions that we produced to kilo Joules. Then, we consulted the instructor with our final answer, he said that we had to divide the enthalpies we found from the reactions that we produced by .05 mol, in order to calculate it with the other enthalpies, because the unit for enthalpy is kJ/mol.
Theoretical Value: Mg(s) + 1/2O2(g)  MgO(s) H = -601.8 kJ
Experimental Value: Mg(s) + 1/2O2(g)  MgO(s) H = -578.4 kJ
Our experimental value is -23.4 kJ more than the theoretical value. Compared to the theoretical value, our percent error is: Percent Error:  578.4 kJ - 601.8 kJ  x 100 % 601.8 kJ = 3.88 % The error can be accounted from mistakes during the experimental process. The Magnesium and the Magnesium Oxide could have been weighed incorrectly. The measuring of the Hydrochloric acid could also have been wrong. Then, there is error from the equipment that we use. Maybe the scale we use for weighing the raw materials was broken. Also, our thermometer could have been…...

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