some phase transitions require an input of heat, such as ___ Other phase transitions require heat to be released such as

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.

dynamic equilibrium is the answer.

a electronegativity decreases beacuse the size of nucleus is bigger.