# Problem: Now consider the following set of reactions:2NO2 → 2NO + O2, H=109 kJ/molN2O4 → 2NO + O2, H=172 kJ/molThe equations given in the problem introduction can be added together to give the following reaction:overall: N2O4 → 2NO2 However, one of them must be reversed. Which one:a. 2NO2 → 2NO + O2b. N2O4 → 2NO + O2

🤓 Based on our data, we think this question is relevant for Professor Orvis' class at GS.

###### Problem Details

Now consider the following set of reactions:

2NO2 → 2NO + O2, H=109 kJ/mol

N2O4 → 2NO + O2, H=172 kJ/mol

The equations given in the problem introduction can be added together to give the following reaction:

overall: N2O4 → 2NO

However, one of them must be reversed. Which one:

a. 2NO2 → 2NO + O2

b. N2O4 → 2NO + O2

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Hess's Law concept. You can view video lessons to learn Hess's Law. Or if you need more Hess's Law practice, you can also practice Hess's Law practice problems.

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What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Orvis' class at GS.