Problem: The energy of activation for the decomposition of 2 mol of HI to H2 and I2 in the gas phase is 185 kJ. The heat of formation of HI(g) from H2 (g) and I2 (g) is -5.65 kJ/mol.Find the energy of activation for the reaction of 1 mol of H2 and 1 mol of I2 in the gas phase.

FREE Expert Solution

We’re being asked to determine the activation energy for the catalyzed reverse reaction.


We’re given the following information:


ΔH = –5.65 kJ/mol for 1 mol the reaction: Recall that the change in enthalpy (ΔH) is the difference in energy between products and reactants. ΔH for the reaction is negative, which means we have an exothermic reaction. This signifies that the reactants are higher in energy than the products.


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Problem Details

The energy of activation for the decomposition of 2 mol of HI to H2 and I2 in the gas phase is 185 kJ. The heat of formation of HI(g) from H2 (g) and I2 (g) is -5.65 kJ/mol.

Find the energy of activation for the reaction of 1 mol of H2 and 1 mol of I2 in the gas phase.

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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 Energy Diagram concept. If you need more Energy Diagram practice, you can also practice Energy Diagram practice problems.

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Based on our data, we think this problem is relevant for Professor Rosenthal's class at VANDERBILT.