When a chemical system is at equilibrium, the concentrations of the reactants are equal to:. 1. the concentrations of the products.
2. the concentrations of the reactants and products have reached constant values.
3. the forward and reverse reactions have stopped. the reaction quotient, , has reached a maximum.
4. the reaction quotient, , has reached a minimum.

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.

i believe it is a.) released into

explanation:

the answer to your question is c