Question

1. With the aid of a Hess cycle, determine the enthalpy of the decomposition reaction of sodium nitrate, NaNO3 to sodium nitrite, NaNO2 and oxygen, O2. [5]

Enthalpy of formation of NaNO3 = -468 kJ/mol
Enthalpy of formation of NaNO2 = -369kJ/mol

Answer 1

Step-by-step explanation:

2NaNO₃ = 2NaNO₂ + O₂

NaNO₃ = NaNO₂ + 1/2 O₂

- 468 kJ -369 kJ 0 kJ

enthalpy of decomposition reaction

= - 369 - ( - 468 ) kJ

= 99 kJ / mol .