. When is separation of substances necessary ?Name four methods used to separate solid substances ? the one of 2 who send correct answer will get the brainliest and 40 points​

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.