Answer is: because carbon(IV) oxide is released.
For example if baking soda is used for <span>the pizza dough, than on heat carbon(IV) oxide is product of chemical reaction:
2NaHCO</span>₃ → Na₂CO₃ + CO₂ + H₂O.
If we use yeast (<span>single-celled microorganism)</span>, also carbon(IV) oxide produced, because yeast turns sugars into carbon(IV) oxide.
The most accurate way to measure a dry ingredient like flour, sugar or chocolate chips is in terms of its weight, which is measured in regular ounces.
The main pieces of evidence that an exothermic reaction has occurred is an increase in temperature due to the release of energy, a release of energy in the form of light, or a release of gas.
It should be potential energy!!!
