The purpose of this experiment was to find the specific heat formation of magnesium oxide by combining the two heat reactants using Hess’s Law. The purpose was also to measure the delta T which was the final temperature minus the initial temperature of the solution. The claim made was, based on the expected heat formation value found in magnesium metal and hydrochloric acid, the experimental enthalpy was much closer to the expected value in comparison the magnesium oxide and hydrochloric acid. The equations used in this experiment were 1. MG(s)+2HCl(aq)= MgCl2(aq)+ H2(g) 2. MgO(s)+2HCl(aq)=MgCl(aq)+H2O(l) 3. H2(g) +1/2O2(g)=H2O(l). We combined the listed equations we cancelled certain values using Hess’s Law to form magnesium oxide, Mg(s)+1/2O2(aq)=MgO(s). The experimental heat formation of magnesium oxide is -467.684 kJ/mol. Based on the results found, using the correlation coefficient (R2) and the maximum value of temperature final (which was found to be 70.934) we found the correlation between the trend lines (expected) to the experimental. Based on the data found this information supported our claim. There may have been several errors in the experiment one error may have been the lack of recording on time, meaning the stop watch was started later in the reaction. Another reason for error was the lack of taking the first trials measurement forcing us to estimate a mass which through off the results of the experiment in a whole. The final reason for error was not all of the magnesium oxide that was measured was experimented. These error sources listed above, may cause numerous problems for example the estimated mass for the first trial cause the results to skew, giving us a large error percentage of -21% if this trial was taken out the error percentage would be much lower. The stop watch did not start at the same time of the experiment which may cause an increase in the error percentage as well; due to this fault the temperature final would be much...
References: 1. http://en.wikipedia.org/wiki/Exothermic_reaction
2. Chem 147 lab manual fall 2010
3. Chemistry and reactivity 7th ed.
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