Question

Learning Goal: To understand how to use Hess's law to find the enthalpy of an overall reaction. Correct The change in enthalpy, AH, is the heat absorbed or produced during any reaction at constant pressure. Hess's law states that ? H for an overall reaction is the sum of the values for the individual reactions. For example, if we wanted to know the enthalpy change for the reaction PartB What is the enthalpy for reaction 1 reversed? Express your answer numerically in kilojoules per mole. reaction 1 reversed: N204-N2 202 3Mn+302+3MnO2 we could calculate it using the enthalpy values for the following individual steps: Step 1: 4Al+302-+2Al2Os Step 2: 3Mn + 2A1203?3MnO2 + 4A1 Overall: 3Mn + 302?3MnO2 k.J/mol If the enthalpy change is -3352 kJ/mol for step 1 and 1792 kJ/mol for step 2, then the enthalpy change for the overall reaction is calculated as follows: Submit Incorrect; Try Again; 2 attempts remaining AH-3352+1792 -1560 k.J/mol It is also important to note that the change in enthalpy is a state function, meaning it is independent of path. In other words, the sum of the ?? values for any set of reactions that produce the desired product from the starting materials gives the same overall ?? Part C This question will be shown after you complete previous question(s). Provide Feedback

Answer 1

Enthalpy of reaction for N₂ + 2O₂ $\rightarrow$ N₂O₄ is    $\Delta$ H= -8kJ/mol

therefore for reversed reaction i.e., N₂O₄ $\rightarrow$ N₂ + 2O₂ is    $\Delta$ H = 8kJ/mol