CARROLL 3 - Name: Quiz Section: ID Number: Lab Partner:...

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Unformatted text preview: Name: Quiz Section: ID Number: Lab Partner: 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) 5.6 5.6 5.6 Current, A (C/s) 1.93 2 2.03 Time (s) 133.38 138.04 133.99 21.9 22.4 24.8 26.1 26.6 29.0 *Eletrical power input into calorimeter (q), J 1442 1546 1523 343.2 368.1 362.7 358 Standard Dev 13 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 Our goals are to: i) Determine the heat capacity of the calorimeter ii) Measure the heat of fusion of ice iii) Measure the heat of neautralization iv) Determine the enthalpy of hydration magnesium sulfate. 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 guides for what should be included. i) To determine the heat capacity of the calorimeter, water will be added, initial temperature, voltage, current, and time for the temperature to change 4-5C will be recorded. Ccal=q/DT, and q=Ccal*DT. The equation Ccal=Voltage*current*time(s)/DT is used to find the heat capacity. ii) We set the equation of heat lost by the calorimeter equal to the heat gained by the system:-Ccal*DT=(m ice)(DHfusion) + (m ice)(specific heat of water)(DTwater from ice) since we know all the data except for DHfusion, we simply plug the numbers in and solve for DHfusion. iii) q=Ccal*DT, and we use the equation DHneut=CcalDT/mol H2O produced iv) MgSO4(s) ---> Mg(aq) + SO4(aq) DH1 Mg(aq) + SO4(aq) + 7H2O(l) ---->MgSO4.7H2O(s) -DH2 DH=CcalDT/mols solid----------------------------------------------------------------------------------------------- MgSO4(s)+ 7H2O ----> MgSO4.7H2O(s) DHhyd=DH1-DH2 EXPERIMENT 3: CALORIMETRY BE SURE TO USE AN APPROPRIATE NUMBER OF SIGNIFICANT FIGURES *Type an example of the calculations you are performing for q and Ccal. (5 pts) q=voltage*current*time(s) q=5.6*1.93*133.38 q=1442J Ccal= q/delta T Ccal=1442J/(26.1-21.9)Ccal=1442J/(26....
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This note was uploaded on 10/26/2010 for the course CHEM 152 taught by Professor Chiu during the Fall '08 term at University of Washington.

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CARROLL 3 - Name: Quiz Section: ID Number: Lab Partner:...

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