A 4.4-g sample of Colorado oil shale is burned in a bomb calorimeter,which causes 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?

Question

Quizplus · Accepted Answer

First, we need to calculate the total heat absorbed by the water and the calorimeter:

q = (m_water x C_water x ∆T) + (C_cal x ∆T)
q = (1000 g x 4.184 J/g°C x 5.0°C) + (0.10 kJ/°C x 5.0°C)
q = 20.92 kJ + 0.50 kJ
q = 21.42 kJ

This is the total heat released by the combustion of the 4.4 g sample. To find the heat released per gram of oil shale, we can divide this by the mass of the sample:

q/g = 21.42 kJ / 4.4 g
q/g = 4.87 kJ/g

Therefore, the answer is D) 4.9 kJ/g (rounded to two significant figures).

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