Question

If we reverse the reaction to read Z + Q → X + Y, the +ΔH would be a -ΔH. Does this indicate that heat is given off or absorbed in the reverse reaction?
-given off
-absorbed

Answer 1

Answer:

Reactants.  

Step-by-step explanation:

The equation for the reverse reaction is

Z + Q ⟶ X + Y; ΔH < 0

A negative ΔH indicates that the energy has been given off.

The products X + Y are at a lower energy level than the reactants Z + Q, and the excess energy has been transferred to the surroundings.

Answer 2

Answer: The heat is given off in the reaction.

Explanation:

Endothermic reactions are defined as the reactions in which energy of products is more than the energy of the reactants. In these reactions, energy is absorbed by the system. The total enthalpy of the reaction $(\Delta H)$ comes out to be positive.

Exothermic reactions are defined as the reactions in which energy of reactants is more than the energy of the products. In these reactions, energy is released by the system. The total enthalpy of the reaction $(\Delta H)$ comes out to be negative.

So, for the reverse reaction:  $Z+Q\rightarrow X+Y;\Delta H=-ve$

Thus, the heat is given off in the reaction.