en a certain quantity of sucrose is burned in a constant pressure calorime- ter,

Question

en a certain quantity of sucrose is burned in a constant pressure calorime- ter, the temperature of the water rises by 30 K. The combustion reaction is represented by the following C12H22O11 (s) + 1202 (g) 12CO2 (g) + 11H20 (1) (a) (10 points) It is possible to calculate the heat of combustion from the temperature 12122 11 change if you know the heat capacity of the entire system (sucrose solution plus the calorimeter). Describe a valid procedure to determine the heat capacity of the sucrose/calorimeter system experimentally

Explanation / Answer

This is how you determine heat capacity of sucrose + caloriemter:

Qrxn = Qwater + Qcalorimeter

Assume:

qwater will be known --> mass of water; Cp water, Tfinal will be measured and Tinitial is known

Qcalorimeter --> CCal*(Tf-Ti) = Ccal will be claculated

Qrxn = n*HRxn

n = moles of sucrose, we must know how much we added

HRxn = must be known as well, via literature or bibliography

now, setup:

Qrxn = Qwater + Qcalorimeter

-nHRxn = mw*Cpw*(Tf-Tw) + Ccal(Tf-Tw)

substitute data

-mass/MW * HRxn = mw*Cpw*(Tf-Tw) + Ccal(Tf-Tw)

Tf --> Tfinal will be measured AFTER combustion

mw = mass of water measured by us, probably via volume --> mass = Density * volume

then

CCal = (-mass/MW * HRxn - mw*Cpw*(Tf-Tw)) / (Tf-Tw)

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