152 Exp 3 Report - LAB PARTNER: EXPERIMENT 3: CALORIMETER...

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LAB PARTNER: Total Points = 60 pts PURPOSE AND METHOD DATA AND CALCULATIONS A: HEAT CAPACITY OF THE CALORIMETER Run 1 Run 2 Run 3 Voltage, V (J/C) 3.00 3.00 3.00 Current, A (C/s) 2.94 3.36 3.05 Time (s) 129.03 113.00 121.96 23.0 23.8 24.0 27.4 28.2 28.3 *Electrical power input into calorimeter (q), J 1138.04 1139.04 1115.93 5 pts 258.65 258.87 259.52 259.01 Standard Dev 0.45 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 STD = 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 neutralization iv) Determine the enthalpy of hydration magnesium sulfate. Explain how each of these is accomplished in this experiment . (2 pts each = 8 pts): i) Determine the heat capacity of the calorimeter The heat capacity of the calorimeter is determined by adding a known amount of energy (current and voltage) into a known mass of water (60.0g) and measuring the time it takes for the temperature to increase. We plug these values into the following equation and solve for Ccal: Ccal = current * voltage * time / (change in temp). ii) Measure the heat of fusion of ice The heat fusion of ice is determined by adding a measurable mass of ice to a known mass of water in the calorimeter (which now has a known heat capacity) and measuring the total change in temperature. The energy required to change the temperature in the calorimeter will be equal to the energy required to melt the ice and heat the melted ice to the final temperature. iii) Measure the heat of neutralization The heat of neutralization can be determined by combining equal volumes of two different acids (hydrochloric acid and acetic acid) with a strong base (NaOH) in the calorimeter and measuring the total change in temperature. The acid and base react 1:1 to form water. The energy can be calculated as the amount of heat required to change the calorimeter's temperature as follows: q=CcalDT and DH = q/mol H2O. iv) Determine the enthalpy of hydration magnesium sulfate
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This note was uploaded on 04/07/2008 for the course CHEM 152 taught by Professor Chiu during the Winter '08 term at University of Washington.

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152 Exp 3 Report - LAB PARTNER: EXPERIMENT 3: CALORIMETER...

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