Question
Comment on:
(i) ∆U is –ve for exothermic reactions and
(ii) ∆U is +ve for endothermic reactions.
Solution
∆U is –ve for exothermic reactions: Heat evolved is equal to the internal energy change when the reaction is carried out at constant volume and constant temperature. For an exothermic reaction, there is an evolution of heat energy and hence the internal energy of products (Up) will become less than the internal energy of the reactants (UR).
For example,
∆U is +ve for endothermic reactions : Heat absorbed is equal to internal energy, when the reaction is carried out at constant volume and constant temperature. For endothermic reaction, there is an absorption of heat energy and hence internal energy of the product (UP) will become more than the internal energy of the reactant (UR)
For example,
For example,
∆U is +ve for endothermic reactions : Heat absorbed is equal to internal energy, when the reaction is carried out at constant volume and constant temperature. For endothermic reaction, there is an absorption of heat energy and hence internal energy of the product (UP) will become more than the internal energy of the reactant (UR)
For example,
