Calorimetry Experiment

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Calorimetry Experiment

Purpose: The objective of this lab is to determine the enthalpy change for NaOH(aq) + HCl(aq) NaCl (aq) + H2O(l)

Procedure: Before measuring the enthalpy of acid base neutralization, my partner Brian and I determined a calorimeter constant, using a homemade polystyrene calorimeter. With the following formula and data: qhot= cm (Tf-Ti)

qcold=cm(Tf-Ti)

SYSTEMDATASURROUNDINGSDATA
Water coldMass: 50mLWater hotMass: 50mL
C=4.18C=4.18
Ti=20 CTi=31 C
Tf=31 CTf=37 C
Calorimeter95J/g C
Ti=22 C
Tf=28 C

I was able to conclude that my calorimetric constant for this calorimeter is 95J/g C. Next we took 50mL of 1.0 M sodium hydroxide and 50mL of 1.0M hydrochloric acid at a room temperature of 22 C and combined the two solutions in the homemade calorimeter, stirring steadily with a magnetic stir rod. After measuring the temperature of the solution, we resulted with the following data:

SYSTEMDATASURROUNDINGSDATA
Acid50mL of 1.0 M HCl
Moles=0.05Water(solvent & Surroundings)Mass: 100g
Base50mL of 1.0 M NaCl
Moles=0.05C= 4.18
Ti=22 C
Tf=28 C
CalorimeterC= 95 J/g C
Ti= 22 C
Tf=28 C

Conclusion: Given that heat produced from the reaction results in +1938.0J from the surroundings and -1938.0J from the system, I conclude from this experiment that the system loses heat during acid base reaction and that the surroundings gain heat. Sources of error include the quality of the calorimeter. The lid does not insulate well, because it has a hole to accommodate for the thermometer, which means that this is an area where heat of reaction could be lost to the surroundings. Also, Brian and I did not determine the mass of the assembled calorimeter, nor did we determine the mass of the calorimeter and water, therefore we were unable to determine the exact density of our final mixture, and needed to look this up on a density chart, with the assumption that all of our...
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