A 2.50 g sample of pitted prunes was burned in a bomb calorimeter containing 2110 g of water. The temperature of the water increased from 22.50°C to 25.76°C. How much heat, in joules, did the prune sample release when it burned? [C_water = 4.184 J/(g°C)]

Question

Quizplus · Accepted Answer

First, calculate the change in temperature of the water:
ΔT = (25.76°C - 22.50°C) = 3.26°C
Next, calculate the amount of heat absorbed by the water:
q = (2110 g) x (4.184 J/(g°C)) x (3.26°C) = 28958.27 J
This is the amount of heat released by the burning prune sample, so we need to convert it to joules:
28958.27 J = 2.89 x 10^4 J
Finally, we need to divide this energy by the mass of the sample of pitted prunes:
q/g = (2.89 x 10^4 J) / (2.50 g) = 1.156 x 10^4 J/g
This is the amount of energy released per gram of pitted prunes. The answer must be expressed in scientific notation:
Answer: C
 First, calculate the change in temperature of the water: ΔT = (25.76°C - 22.50°C) = 3.26°C. Next, calculate the amount of heat absorbed by the water: q = (2110 g) x (4.184 J/(g°C)) x (3.26°C) = 28958.27 J. This is the amount of heat released by the burning prune sample, so we divide by 2.50 g to find the energy per gram: (2.89 x 10^4 J) / (2.50 g) = 1.156 x 10^4 J/g. Therefore, the answer is choice C.

A 250 G Sample of Pitted Prunes Was Burned in a a Bomb