Experiment 12: Calorimetry Essay examples

1899 WordsSep 28, 20128 Pages
| | |Experiment 12- Calorimetry and Hess’s Law | | | | | |Jenna Hyde | |Lab partners:…show more content…
| | | | |reaction, cleared back up.| | |MgO |n/a |n/a | |.501 | Calculations Part A Calculations Trial 1 Mass of cold water: [pic] = 1.00 (g/mL)X 50.0mL= 50 g Tf from graph by extrapolation: 35.5 degrees Celsius ΔTHW=Tf-Ti= 35.5C-54.0C= -18.5C ΔTCW=Tf-Ti=35.5C-22.5C=13.0C qHw=mcΔTHW=(50.0g)(4.184 J/gC)(-18.5C)= -3870 J or -3.87 kJ qCW=mcΔTCW=(50.0g)(4.184 J/gC)(13.0C)= 2720J or 2.72kJ qcal for the cup: |qHW|=|qCW|+qcal 3870=2720+qcal qcal=1150J or 1.15kJ qcal=CcupΔT 1150J=Ccup(13.0C) Ccup=88.4J/C Trial 2 Mass of cold water: [pic] = 1.00 (g/mL)X 50.0mL= 50 g Tf from graph by extrapolation: 36.1 degrees Celsius ΔTHW=Tf-Ti= 36.1C-51.0C= -14.9C ΔTCW=Tf-Ti=36.1C-23.7C=12.4C qHw=mcΔTHW=(50.0g)(4.184 J/gC)(-14.9)= -3120 J or -3.12 kJ qCW=mcΔTCW=(50.0g)(4.184 J/gC)(12.4C)= 2590J or 2.59kJ qcal for the cup: |qHW|=|qCW|+qcal 3120=2590+qcal qcal=530J or 0.530kJ qcal=CcupΔT 530J=Ccup(12.4C) Ccup=42.7J/C Average Ccup=(88.4+42.7)/2=65.55=65.6 J/C Part B Calculations Tf from graph by extrapolation: 29.7C Mass of HCl: [pic] = 1.00 (g/mL)X 100.0mL= 100 g ΔTCW=Tf-Ti= 29.7C-23.0C=6.7.C
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