this was given by professor to help Box Stirrer Figure 18.2: Bomb Calorimeter Fo
ID: 1059641 • Letter: T
Question
this was given by professor to help
Box Stirrer Figure 18.2: Bomb Calorimeter Focus Questions: 1) How much energy is released when food burns in the body? 2) How is the caloric content of food determined? Procedure: Part 1: Determination ofthe Calorimeter Constant 3.00 g of glucose was placed on the sample holder in a bomb calorimeter. The initial temperature inside the calorimeter was 2490 °C After the ignition of the sample, the temperature was monitored. The maximum temperature was 29.20°C. Using the data in the appendix of the textbook, determine AH for the combustion of glucose (eq 1). Determine the calorimeter constant.
Explanation / Answer
Write combustion reaction of glucose
C6H12O6(s) + 6O2(g) ---- > 6CO2 (g) + 6H2O(l)
We use appendix to find delta H of above reaction
Delta Hrxn = Delta H[ ( 6CO2 + 6H2O) – ( C6H12O6 + 6 O2) ]
= 6 [ (-393510 + (-285830)] – (-1273300 + 6 x 0)
=-2802740 J
Use this delta H and find calorimetric constant
Delta H =- Qcal/n
Q cal =- Kcal x delta T
n is number of moles
Lets put for Q cal and n and find Kcal
Delta H = -Kcal x delta T / ( Mass of glucose/molar mass glucose)
Delta H =- Kcal x delta T x molar mass of glucose /mass of glucose
Kcal = -delta H x mass of glucose / (delta T x molar mass of glucose )
= (-(-2802740 J x 3.00 g / ( (29.29-24.9) deg C x 180.1559 g per mol) )
= 10631.41 J/deg C
Answer is 10631.41 J/degC
answer in 10.6 kJ/deg C
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