<span>If all chemical reactions that release free energy tend to occur spontaneously,why haven't all such reactions already occurred? One reason is that most reactions require an input of energy to get started.Before it is possible to form new chemical bonds,even bonds that contain less energy,it is first necessary to break the existing bonds,and that takes energy.The extra energy required to destabilize existing chemical bonds and initiate a chemical reaction is called activation energy.</span>
Combining the two clear colorless liquids is a chemical change because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically.
Answer:
H3PO4 is the formula for hydrophosphoric acid
If you mean what group of elements react the most, the answer is the alkali metals and the halogens because they both only either need to gain or lose one electron. If you mean the most reactive element, it would be fluorine because it has the most electronegativity.