Question

One gram sample of $NH _{4} NO _{3}$ is decomposed in a bomb calorimeter. The temperature of the calorimeter increases by $6.12\, K$. The heat capacity of the system is $1.23\, kJ / g / deg$. What is the molar heat of decomposition for $NH _{4} NO _{3}$ ?

• A. $-7.53\, kJ / mol$
• B. $-398.1\, kJ / mol$
• C. $-16.1 \,kJ / mol$
• D. $-602\, kJ / mol$

Answer 1

Answer: (D)

$-602\, kJ / mol$

Answer 2

Heat of decomposition, $\Delta E=m \cdot s \cdot \Delta T$ $=1 \times 1.23 \times 6.12=7.5276\, kJ$ Molar heat of decomposition for $NH _{4} NO _{3}$ $=7.5276 \times 80=602.2 \,kJ$