Discuss what all the values of w and q should be if a system is exothermic. Then discuss what all the values of w and q should be if a system is endothermic.

In an exothermic reaction, q is negative while w is positive.

In an endothermic reaction, q is positive while w is negative

Explanation:

An Exothermic reaction is one in which the heat content of the system is greater than the heat content of the surroundings. As a result of this, heat (measured by Q) is given off into the surroundings and the surroundings is hotter than than the system. The heat emitted does work against the surroundings, hence the value of work done W is positive.

An endothermic reaction is the opposite of an exothermic reaction.

During an endothermic reaction, the heat content of the reactants is lesser than the heat content of the products. The surroundings then does work on the system , resulting in heat (measured by Q) being absorbed from the surroundings into the system, making the system hotter than than the surroundings. The value of work done W in an endothermic reaction is negative because the system does work against the surroundings.