Question

Use the standard reaction enthalpies given below to determine ∆ H ° r x n for the following reaction: 2 N O ( g ) + O 2 ( g ) → 2 N O 2 ( g ) GIVEN: N 2 ( g ) + O 2 ( g ) → 2 N O ( g ) △ H ° r x n = + 183 k J

Answer 1

The standard enthalpy change for the reaction 2NO(g) + O2(g) → 2NO2(g) can be directly taken from the third given reaction, which is -114.1 kJ.

Step-by-step explanation:

To determine the standard enthalpy change (∆H°rxn) for the given reaction 2NO(g) + O2(g) → 2NO2(g), we can utilize Hess's law which states that if a reaction can be expressed as a series of steps, the enthalpy change for the overall reaction will be the sum of the enthalpy changes for the individual steps. In this case, we can piece together reactions with known enthalpies to find the desired enthalpy change.

The given equations and their respective enthalpy changes are:

• N2(g) + O2(g) → 2NO(g), ∆H° = +183 kJ
• N2(g) + O2(g) → NO2(g), ∆H° = +33.2 kJ/mol
• 2NO(g) + O2(g) → 2NO2(g), ∆H° = -114.1 kJ

We can directly use the third reaction and its enthalpy change as it matches the target reaction. Thus, the standard enthalpy change for the reaction 2NO(g) + O2(g) → 2NO2(g) is -114.1 kJ.