The heat required to raise the temperature of m (kg) of a liquid from T1 to T2 at

Chapter 8, Problem 8.12

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The heat required to raise the temperature of m (kg) of a liquid from T1 to T2 at constant pressure is Q H m Z T2 T1 CpT dT (1) In high school and in first-year college physics courses, the formula is usually given as Q mCp T mCpT2 T1 (2) (a) What assumption about Cp is required to go from Equation 1 to Equation 2? (b) The heat capacity (Cp) of liquid n-hexane is measured in a bomb calorimeter. A small reaction flask (the bomb) is placed in a well-insulated vessel containing 2.00 L of liquid nC6H14 at T 300 K. A combustion reaction known to release 16.73 kJ of heat takes place in the bomb, and the subsequent temperature rise of the system contents is measured and found to be 3.10 K. In a separate experiment, it is found that 6.14 kJ of heat is required to raise the temperature of everything in the system except the hexane by 3.10 K. Use these data to estimate Cp[kJ/(molK)] for liquid n-hexane at T 300 K, assuming that the condition required for the validity of Equation 2 is satisfied. Compare your result with a tabulated value.