Question

The following sequence of reactions occurs in the commercial production of aqueous nitric acid:

4NH₃(g)+5O₂(g)→4NO(g)+6H₂O(l)ΔH=−907kJ
2NO(g)+O₂(g)→2NO₂(g)ΔH=−113kJ
3NO₂(g)+H₂0(l)→2HNO₃(aq)+NO(g)ΔH=−139kJ

What is the net enthalpy change for the overall reaction for the production of aqueous nitric acid from NH₃, O₂, and H₂O?

a) -1259 kJ
b) -1259 kJ
c) -1159 kJ
d) -1059 kJ

Answer 1

The net enthalpy change for the overall reaction for the production of aqueous nitric acid from NH₃, O₂, and H₂O is -1159 kJ.

Step-by-step explanation:

To find the net enthalpy change for the overall reaction for the production of aqueous nitric acid, we need to sum up the enthalpy changes for each individual reaction and account for stoichiometry. The given reactions are:

4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l) (ΔH = -907 kJ)

2NO(g) + O₂(g) → 2NO₂(g) (ΔH = -113 kJ)

3NO₂(g) + H₂0(l) → 2HNO₃(aq) + NO(g) (ΔH = -139 kJ)

To calculate the net enthalpy change, we need to sum up the enthalpy changes for the individual reactions:

Net enthalpy change = ΣΔH

= (-907 kJ) + (-113 kJ) + (-139 kJ)

= -1159 kJ

Therefore, the net enthalpy change for the overall reaction is -1159 kJ.