caliormetry katie - Name: Katherine Beyer ID Number:...

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Name: Katherine Beyer Quiz Section: BE ID Num 1026131 Lab Partner:David Ambramov 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) 3.3 3.3 3.3 Current, A (C/s) 3.11 3.1 3.1 Time (s) 150 151 149 22.4 22.7 22.7 26.5 26.9 26.9 *Eletrical power input into calorimeter (q), J 1395 1545 1524 340.0 367.8 362.9 357 Standard Dev 15 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)". B: HEAT OF FUSION OF ICE Run 1 Run 2 357 357 Initial temperature, o C Final temperature, o C *Calorimeter Constant, C cal, J/ o C Average, C cal C cal (Average), J/ o C Our goals are to: i) Determine the heat capacity of the calorimeter In order to determine the heat capacity of the calorimeter, we need to determine the heat gained by the calorimeter over a change in temperature. In order to obtain the heat gained by the calorimeter, we will pass a fixed current througha heat resistor. The heat gained by the caliormeter can be easily established by the equation q cal (J) = curent (C/s) x Voltage (J/C) x time (s), using the information that was gathred from the experiment. The heat capacity of the calorimeter id euqal to the heat gained divided by the change in temperature, we need to measure the initial and final temperatures. By calculating the final and initial temperatures, we can calculate the heat capacity using the equation: C cal = (q cal )/(ΔT) = ii) Measure the heat of fusion of ice To calculate the heat of fusion we know that the energy lost by the calorimeter is equal to the energy to melt ice and the heat gained by the ice/water. The heat lost by the calorimeter can be determined by the heat capacity of the calorimeter (already determined in part i) and the change in temperature of the calorimeter. The heat gained by the ice is determined by the mass of the ice added, the heat capacity of water and the change of temperature of the ice/water. Since the mass of the ice can be measured as can the change in temperature of the ice/water and the capacity of water in commonly known the heat gained by ice/water can be calculated. Overall the heat of fusion can be calculated with: (-qcal) =(mice)(-ΔHfusion) + (qwater/ice). Where qcal = -(Ccal)(ΔTcal) = (qcal)/(Tf - Ti) and qice/water = (mice)(Cwater) (ΔTwater/ice) = (mice)(Cwater)(Tf - Ti). iii) Measure the heat of neautralization By finding the heat lost by the reaction per mole of water created one can determine the heat of neutralization. To determine the moles of water, you first find the moles of acetic acid, sodium hydroxide and hydrochloric acid that are reacted during the equation as well as implementing the stoichiometric equation to obtain the correct number of moles. The heat lost by the two exothermic reactions can be determined by calculating the heat gained by the calorimeter. The exothermic reactions used
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This note was uploaded on 04/09/2011 for the course CHEM 152 taught by Professor Chiu during the Spring '08 term at University of Washington.

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caliormetry katie - Name: Katherine Beyer ID Number:...

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