<span>the distance between peaks of a wave</span>
I don't fully understand your question, but I believe that plants have functions that are vital to the planet. They take sunlight, make it into food for themselves, and release oxygen that we need to survive.
<span>Hydration can occur when one mole of sodium acetate trihydrate is heated. Sodium acetate or NaC2H3O2 3H2O contains three water molecules within each unit in the crystal. The corresponding amount of hydration energy is already released when sodium acetate absorbs water and is then converted to sodium acetate trihydrate.</span>
There are impurities in the substances.
The reaction might not go to completion.
The amount of one of the reactants might be measured incorrectly.
The expected amount might be based on measurements with error.