The activation energy of an endothermic

The activation energy of an endothermic reaction must be greater that the required ΔH

Explanation:

In chemistral reaction, when you have endothermic reaction, the energy of reactives must be less that energy of products, because we need energy to make them. As we need it, that's why we say that it is endothermic reaction, remember that if you want to calculate ΔH, you should do a substraction between, activation energies.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.