Chem152_Thermo1_Report_041410 (1)

# Chem152_Thermo1_Report_041410 (1) - Name: Gordon Sewart ID...

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Name: Gordon Sewart Quiz Section: AL ID Number: 0927625 Lab Partner: Josh Schwartz 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) 3.1 3.1 3.1 Current, A (C/s) 2.1 2.12 2.13 Time (s) 255 230 232 24.4 24.7 24.9 29.2 29.0 29.1 *Eletrical power input into calorimeter (q), J 1660 1512 1532 345.8 351.5 364.7 354 Standard Dev 10 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 2 354 354 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 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 ) Part 1: We can find the heat capacity based on the change in teperature when a known amount of heat is added to the calorimeter containing a known amount of water. With a constant voltage and current, we'll use the formula Ccal=[voltage(J/C)*current(C/S)*time(S)]/(Tf-Ti) to find the heat capacity as a reference for calculation the heat of fusion and neutralization oin ohter processes. Part 2: By knowing the initial values of the amount of water in the calorimeter, the weight of the ice added, the temperature of the ice added, and the temperature of the water before ice is added, we can measure the heat of fusion of ice. Since -q=(heat to melt ice) + (heat to warm water that was ice) and q=(mass of ice)*(dH of fusion) + (mass of ice) (4.184 J/g*C)(dT of water that was ice), we can set the two equations equal to one another, leaving two unkowns: dH of fusion and the mass of the ice. The mass of the ice can be determined by weighing the calorimeter before and after the addition of ice, thus allowing us to solve for the heat of fusion of ice.

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## This note was uploaded on 05/17/2010 for the course CHEM 152 taught by Professor Chiu during the Spring '08 term at University of Washington.

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Chem152_Thermo1_Report_041410 (1) - Name: Gordon Sewart ID...

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