LapReport6.pdf - Using Enthalpy to Design a Hand Warmer By Brandon Carter Lab Partner Gabe Neal Observations\/Results\/Data Part 1 Initial Temperature of

# LapReport6.pdf - Using Enthalpy to Design a Hand Warmer By...

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Using Enthalpy to Design a Hand Warmer By Brandon Carter Lab Partner: Gabe NealObservations/Results/Data Part 1: Initial Temperature of cold distilled water: 19.8 ºC Temperature of 100 mL of Hot Water: 67.0 ºC TMix = 41.7 ºC Tavg = 43.4 ºC Part 2: Initial Temperature of Water: 20.1 ºC Mass of MgSO4: 5.02 g Highest (Final) Temperature: 27.7 ºC Part 3: Initial Temperature of Water: 19.6 ºC Mass of Na2CO3: 5.02 g TMax (Final Temp.): 23.2 ºC Analysis/Calculations Part 1: qwater = (200.0 g) * (4.184 J / g ºC) * (41.7 ºC - 43.4 ºC) = -1420 J
CCal = (-1420 J) / (41.7 ºC - 19.8 ºC) = -64.8 J / ºC Part 2: qcal = (27.7 ºC -20.1 ºC) * (64.8 J / ºC) = (7.6 ºC) * (64.8 J / ºC) = 490 J qaq = (100.0 g + 5.02 g) * (4.184 J / g ºC) * (7.6 ºC) = (105.0 g) * (4.185 J / g ºC) * (7.6 ºC)= 3,300 J q soln = - (3300 J - 490 J) = -2810 J MW of Mg SO4= 24.31 + 32.0 + (4*16.00) = 120.31 g/mol nsolute = 5.02 g / 120.31 g/mol = .0417 mol qsol / mol = -2810 J / .0417 mol = -67386.09 J / mol → -67.4 kJ / mol Part 3: Na2CO3 qCal = (23.2 ºC - 19.6 ºC) * (64.8 J/ºC) = (3.6 ºC) * 64.8 J/ºC = 230 J
q aq = (100.0 g +5.02 g) * (4.184 J / g ºC) * (3.6 ºC) = (105.0 g) * (4.184 J / g ºC) * 3.6 ºC = 1,600 J qsoln = - (1600 J - 230 J) = -1370 J nSolute = 5.02 g / 105.99 g/mol = .0474 mol qsol / mol= -1370 J / .0474 = -28,902.95 J / mol → -28.9 kJ / mol NH4Cl qcal = (17.0 ºC - 20.8 ºC) * (54.0 J / ºC) = (-3.8 ºC) * (54.0 J / ºC) = -2.1 x 10 2 J qaq = (100.0 g + 5.00 g) * (4.184 J / g ºC) * (17.0 ºC - 20.8 ºC)

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