Question

A 50 gram sample of delicious pork rinds is placed in an open, constant pressure calorimeter that contains 3000 grams of water. The temperature of the water increases by 47◦C when the pork rinds are combusted. The heat capacity of water is 4.184 J/g ◦C. Assume the heat lost to the calorimeter itself or to the air is negligible. Which of the following is correct for the SYSTEM?

1.) ∆U = +590 kJ

2.) ∆U = −11.8 kJ

3.) ∆H = −11.8 kJ

4.) ∆H = +590 kJ

5.) ∆U = −590 kJ

6.) ∆H = +11.8 kJ

7.) ∆U = +11.8 kJ

8.) ∆H = −590 kJ

Answer 1

for ther water

q= m C T and q = delta H

q = 3000 grams ( 4.184 J/g-C) (47 C)

q = 589944 joules

q = 589.944 kiloJoules

q ( @ 3 sig figs) = 590 kJ gained by the water.

which equals -590kJ lost by the pork

your answer is: #8. delta H = -590 kJ