A 1.500 g sample of benzoic acid (deltaU_combustion = -26.43 kJ/g) is burned in a bomb calorimeter, raising the temperature of the bomb + water from 23.55 C to 27.32 C. In a second experiment, a 0.952 g sample of an unknown solid fuel is burned in the same calorimeter, and the temperature rises by 2.41 C.
What is the heat of combustion per gram of the unknown fuel?
- A
-12.5 kJ/g
- Bcheck_circle
-26.6 kJ/g
- C
-2.41 kJ/g
- D
-39.65 kJ/g
Explanation
q = C_cal * deltaT = 10.51 * 2.41 = 25.33 kJ released. Per gram: 25.33 / 0.952 = 26.6 kJ/g; sign negative for combustion.