chemlab3 - NAME and ID Number: Christina Hong 086260 Quiz...

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NAME and ID Number: Christina Hong 086260 LAB PARTNER: Travis Huynh Quiz Section: AR Total Points = 60 pts (5 notebook, 55 template) PURPOSE AND METHOD DATA AND CALCULATIONS A: HEAT CAPACITY OF THE CALORIMETER Run 1 Run 2 Run 3 Voltage, V (J/C) 05.2 J/C 05.2 J/C 05.2 J/C Current, A (C/s) 2.11 C/s 1.93 C/s 1.90 C/s Time (s) 161.5 sec 177.94 sec 188.03 sec 23.8°C 24.1°C 23.1°C 28.1°C 27.9°C 27.4°C *Eletrical power input into calorimeter (q), J 1771.978 J 1785.81 J 1857.73 J 412.09 469.95 432.03 438.02 Standard Dev 29.39 5 pts Help In Excel type "=average(range of values)" Instead of entering a range, just click at one end of the values and drag mouse to the other end For standard deviation, in Excel type "=stdev(range of values)". Initial temperature, o C Final temperature, o C *Calorimeter Constant, C cal, J/ o C Average, C cal Explain how each of these is accomplished in this experiment. ( 2 pts each = 8 pts ) Hint: use the leading questions in the P/M secions of lab reports 1 and 2 as a guide. i) Determining the heat capacity of the calorimeter is the first part of this lab. In order to accomplish this part A of the experiment, I will be running three trials. In each trial I will be recording the voltage, current, time, and the initial and final temperature °C. From the data of all three runs, I will be asked to calculate the electrical power input into calorimeter and heat capacity of the calorimeter. Then, I will be taking the average of the Ccals as my Ccal for the rest of the experiment. The equation I will be using to determine the electrical power input into calorimeter is q(J)=current (C/s) x voltage (J/C) x time (s). The equation used to determine the heat capacity of the calorimeter is Ccal: qcal/(Tf-Ti). ii) Measuring the heat of fusion of ice is the second part of this lab. In order to accomplish part B of the experiment, I will be conducting two trials. For both runs, I will be determining the energy required to convert H2O(s) to H2O (l). I will be taking the calculated Ccal from part A of the experiment and use it to help calculate the heat lost by calorimeter (q cal). I will also be asked to calculate heat of fusion of ice and the heat to warm water from ice temperature. The overall equation used to determine the heat lost by calorimeter (q cal) and the heat to warm water from ice temperature: -q=-CcalΔTcal=heat to melt ice+heat to warm water that was ice. The equation that I will use to calculate the heat of fusion of ice: heat gained by ice/water=q=(m-ice)(ΔHfusion)+[(m-ice)(4.184 J/g°C)(ΔT water that was ice)]. iii) Measuring the heat of neautralization is the third part of the this lab. In this part of the experiment, I will be determining the heat released by an exothermic reaction, specifically the neutralization of acid by NaOH. Also, I will be determining the enthalpy required to hydrate magnesium sulfate. I will be asked to calculate the moles of H2O formed from reaction, the magnitude of q, and the enthalpy for both HCl+NaOH and HOAc+NaOH. To calculate the magnitude of q,
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This note was uploaded on 04/13/2010 for the course CHEM 152 taught by Professor Chiu during the Winter '08 term at University of Washington.

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chemlab3 - NAME and ID Number: Christina Hong 086260 Quiz...

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