Question

If we reverse the reaction to read Z + W -> X + Y, the +deltaH would be a -delta H. Does this indicate that heat is given off or absorbed in the reverse reaction

Answer 1

In this reaction heat is released

Step-by-step explanation:

Exothemic Reactions : Those reactions in which heat is released when the products are formed .

For such reaction The enthalpy change is negative.

`\Delta H= -` for exothermic reaction

Endothermic Reactions : Those reaction which proceed by absorbing heat . Here heat is absorbed. The enthalpy change for such reactions is positive.

`\Delta H= +`

When the direction of reaction reverses , the value of H also changes.

In the given reaction,

`X + Y\rightarrow Z +Q`

`\Delta H= +` = heat is absorbed

So,

`Z+Q\rightarrow X+Y`

`\Delta H= -` = heat is released

Exothermic reactions are more spontaneous as compared to endothermic ractions. This means that they proceed own their own . Only little amount of energy is supplied to exothermic reaction to produce the prodct.