Question

1 gram sample of $N{H}_{4}N{O}_3$ 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 $N{H}_{4}N{O}_3$?

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

Answer 1

The correct option is D $602kJ/mol$

The expression for the heat evolved is $q=mS\Delta T$
When 1g of ammonium nitrate decomposes, the heat evolved is
q=1×1.23×6.12

When 1 mole of ammonium nitrate decomposes, the heat evolved is q=1×1.23×6.12×80 = 602.21 kJ/mol