Chem 1B Lab Saul Ruiz Experiment 9 Thermochemistry The purpose of this experiment was to foster an understanding of temperature along with heat and heat capacity by using a calorimeter to measure the specific heat if a metal the heat of the solution and the heat of the neutralization reaction This is seen in four parts of the experiment which include testing the heat capacity of cold water before and after it is mixed with hot water finding the heat capacity of an unknown metal finding the heat of a solution using solid NH4NO3 and finally calculating the molar heat of neutralization of a strong acid strong base reaction NH4NO3 s NH4 aq NO3 aq NH4NO3 s H2O l NH4OH l HNO3 l HCl aq NaOH aq NaCl aq H2O aq H aq OH aq H2O l In this experiment Ccal represents the heat capacity of the calorimeter which is utilized to determine the heat gained by the water and the calorimeter In measuring it twice it exhibits accuracy and precision since having only one value does not allow comparison which may deter the desired results For this experiment the Ccal value that was calculated was 89 5 Jg 1 C 1 The values of Ccal may be consistent but it is notentirely certain since only one reading of Ccal was taken for the experiment The value for the Cmetal was 0 51 Jg 1 C 1 and the unknown metal was Fe Iron The calculated atomic mass was 49 0 g mol 1 whereas the actual atomic mass of the metal was 55 85 g mol 1 The difference of these two values ends up being roughly 6 85 g mol 1 For Part 3 the experimental value for H was 10 9 kJ mol 1 whereas the calculated experimental value was 28 6 kJ mol 1 In Part 4 the experimental value for H was 70 kJ mol 1 whereas the calculated value was 55 83 kJ mol 1 Various sources of error were present in this experiment which would have most likely thrown our values off in all parts of the experiment For Part One one source of error could have either been variances in temperature as the water might have been too cold or too hot Another source of error here may have been not rinsing the graduated cylinder with hot water which also could have altered the temperature thus changing the qc and qh values In Part Two sources of error may possibly stem from the Bunsen Burner not being as effective as it should have been which would have made the boiling water cooler than it should ve been or delayed the amount of time it takes to boil the water A source of error in Part 3 could have been that the calorimeter was either stirred too vigorously or not stirred enough since either of those can change the temperature readings Finally for Part Four the temperatures of the HCl and NaOH must be nearly the same 0 2 C of each other which could have created a source of error in the experiment
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