With exergonic reactions, imagine you are skiing. After you get off the chairlift, you are in a reactants position. The first step is to get to your trail, in which case you would have to ski-walk around, and put in some energy. You may even have to ‘cross-country’ yourself over to another side of the mountain peak. As such, you are almost putting in energy trying to reach your transition state. Finally, when you reach your transition state, or when you reach your trail, you can happily, freely ski down the mountain, as if you are skiing down from your transition state to a product state, which would relate to being at the base of the mountain, where you have less energy. Because you started out at the top of the mountain and ended up at the bottom, however, you lost ‘height,’ or energy in this case, and therefore this was an exergonic process.
