When two your substances are combined so that each of the pure substances retains its own properties the result is a(n)? a. mixtureb. isotopec. elementd. compound

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.

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements