Question

A 3.6g sample of Colorado oil shale is burned in a bomb calorimeter, causing the temperature of the calorimeter to increase by 5.0°C. The calorimeter contains 1.00 kg of water (heat capacity of H₂O = 4.184 J/g°C), and the heat capacity of the empty calorimeter is 0.10 kJ/°C. How much heat is released per gram of oil shale when it is burned?

a. 21 kJ/g
b. 42 kJ/g
c. 0 kJ/g
d. 5.9 kJ/g
e. 0.17 kJ/g

Answer 1

To determine the heat released per gram of oil shale when burning it in a bomb calorimeter, the total heat absorbed by both the calorimeter and the water it contains was calculated and divided by the mass of the oil shale to get approximately 5.9 kJ/g.

Step-by-step explanation:

To calculate the amount of heat released per gram of oil shale when it is burned in a bomb calorimeter, we first determine the total heat absorbed by the calorimeter and its contents (the water). The calorimeter absorbs 0.10 kJ/°C × 5.0°C = 0.5 kJ and the 1.00 kg of water absorbs 4.184 J/g°C × 1000 g/kg × 5.0°C = 20920 J or 20.92 kJ. Therefore, the total heat released is 0.5 kJ + 20.92 kJ = 21.42 kJ. This heat was released by burning 3.6 g of oil shale. To find the heat released per gram, divide the total heat by the mass of the oil shale: 21.42 kJ / 3.6 g = 5.95 kJ/g, which can be rounded to 5.9 kJ/g (option d).