Which of these statements is not true about chemical reaction rates? a. the reaction rates can change. b. the reaction rates can increase. c. the reaction rates can decrease. d. the reaction rates are always constant.

3

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.