Error in the text regarding this lesson

[Bernard NebelKeymaster]

This lesson makes the point that spontaneous chemical reactions (reactions that go by themselves) are like borders rolling down a hill. They go toward greater stability (lesser potential energy). Therefore, energy is given off in the process. The burning of carbon (charcoal,) is a prime example,                           C + O₂   —> CO₂  + energy. 

The text gives the baking soda-vinegar reaction as another example. This is an error. This particular reaction actually absorbs energy making the reaction container feel cooler. This is not an exception to the rule — it involves two coupled reactions — but the explanation is long and complex. It will be best to  omit this reaction from discussion.

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