The change in enthalpy refers to the amount of heat absorbed or heat evolved in a reaction which is carried out at constant pressure.
The change in enthalpy of a reaction is equal to the sum of formation of products minus sum of formation of reactants. It is denoted by
.
The given reaction is:
![Zn + Cs_(2)SO_(4) \rightarrow 2Cs + ZnSO_(4)](https://img.qammunity.org/2019/formulas/chemistry/high-school/ppbc7qmuvlxglnjl61gyft464mvxxoseys.png)
![\Delta H = \Delta H_(f)^(0)(products))-\Delta H_(f)^(0)(reactants))](https://img.qammunity.org/2019/formulas/chemistry/high-school/fogzkp6aj0v9e8c2rt4cejj65eybx9novb.png)
Substitute the given values
(products) and
(reactants) in above formula, we get
![\Delta H = -1,063 kJ -(-1,400 kJ)](https://img.qammunity.org/2019/formulas/chemistry/high-school/6e25gi18tzw67x9qhuf6o9o3t5uy34oupt.png)
=
![+ 337 kJ](https://img.qammunity.org/2019/formulas/chemistry/high-school/twovkpcmh5abk2crued72cf2efz156zmaz.png)
Thus, change in enthalpy for the single replacement reaction is
![+ 337 kJ](https://img.qammunity.org/2019/formulas/chemistry/high-school/twovkpcmh5abk2crued72cf2efz156zmaz.png)