12. When can a theory be revised? if the general public does not understand the theory

when a new scientist begins working on it

after 10 years

if new knowledge expands and corrects our understanding

if new knowledge expands and corrects our understanding

Explanation:

However, science is always changing. As new evidence is uncovered, a theory may be revised or replaced by a more useful explanation.

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.