When 1.010 g of sucrose (C₁₂H₂₂O₁₁) undergoes combustion in a bomb calorimeter, the temperature rises from 24.92 °C to 28.33 °C. Find ΔE_rxn for the combustion of sucrose in kJ/mol sucrose. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 4.90 kJ/°C.

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SORT You are given the mass of sucrose, the heat capacity of the calorimeter, and the initial and final temperatures. You are asked to find the change in internal energy for the reaction. STRATEGIZE The conceptual plan has three parts. In the first part, use the temperature change and the heat capacity of the calorimeter to find 9cal. In the second part, use qcal to get aixn (which just involves changing the sign). Since the bomb calorimeter ensures constant volume, 9rxn is equivalent to A Exn for the amount of sucrose burned. In the third part, divide qxn by the number of moles of sucrose to determine AErxn per mole of sucrose. GIVEN: 1.010 g C12H22011 T= 24.92 °C T= 28.33 °C Ccal FIND: AErxn CONCEPTUAL PLAN Ccal, AT AErxn = 4.90 kJ/°C qcal qcal Ccal XAT 9rxn=cal 9rxn mol C12H22011 qcal 9rxn RELATIONSHIPS USED 9cal = ccal X AT = -9rxn molar mass C₁2H22011 = 342.3 g/mol