Question

Consider the reaction pathway graph below. Which method would provide evidence to support the inference that this is an exothermic reaction?
add A and C
add E and D
subtract A from C
subtract E from D

Answer 1

Answer: subtract E from D

Explanation:  Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The energy is absorbed in the form of heat and $\Delta H$ for the reaction comes out to be positive.

Exothermic reactions are defined as the reactions in which energy of the product is less than the energy of the reactants. The energy is released in the form of heat and $\Delta H$ for the reaction comes out to be negative.

E- represents energy of reactants

F- represents energy of products

$\Delta H=E_P-E_R$

As $E_P$ < $E_R$ thus

$\Delta H=-ve$

and the reaction is exothermic.

Answer 2

Answer;

-Subtract E from D

Explanation;

• An exothermic reaction is a type of reaction that involves loss of energy to the environment or the surroundings. Endothermic reactions are the other type of reactions in which heat is absorbed from the surroundings into the system.
• In exothermic reactions, the energy of reactants is more than that of the products, and therefore, the enthalpy change is negative.
• Enthalpy change = energy of products - energy of reactants.
• In this case, the method that would provide evidence to support that the reaction is exothermic is by subtracting E from D, as E is the energy of reactants while D is the energy of products.