Questions: When NO(g) reacts with O2(g) according to the following reaction, 57.1 kJ of energy are evolved for each mole of NO(g) that reacts. Complete the following thermochemical equation. ΔH=NJ(g)+O2(g) → 2 NO2(g) ΔH=?
? kJ
Transcript text: When $\mathrm{NO}(g)$ reacts with $\mathrm{O}_{2}(\mathrm{~g})$ according to the following reaction, 57.1 kJ of energy are evolved for each mole of $\mathrm{NO}(\mathrm{g})$ that reacts. Complete the following thermochemical equation. \[ \Delta H=\square \mathrm{NJ}(g)+\mathrm{O}_{2}(g) \rightarrow 2 \mathrm{NO}_{2}(g) \Delta H=? \] $\square$ kJ
Solution
Solution Steps
Step 1: Understand the Reaction and Given Information
The reaction given is:
\[
\mathrm{NO}(g) + \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{NO}_{2}(g)
\]
It is stated that 57.1 kJ of energy is evolved for each mole of \(\mathrm{NO}(g)\) that reacts. This indicates that the reaction is exothermic, and the enthalpy change \(\Delta H\) should be negative.
Step 2: Determine the Enthalpy Change for the Reaction
Since the reaction involves 1 mole of \(\mathrm{NO}(g)\) reacting, the enthalpy change \(\Delta H\) for the reaction is simply the energy evolved, which is \(-57.1\) kJ (negative because the reaction is exothermic).
Final Answer
The thermochemical equation with the enthalpy change is:
\[
\mathrm{NO}(g) + \mathrm{O}_{2}(g) \rightarrow 2 \mathrm{NO}_{2}(g) \quad \Delta H = \boxed{-57.1 \, \text{kJ}}
\]