Question

Calculate the approximate enthalpy of the reaction in joules. Estimate that 1.0 mL of vinegar has the same thermal mass as 1.0 mL of water. It takes 4.2 joules to change 1.0 grm (1.0 mL) of water 1.0 Celcius. Is it endotherrmic or exothermic? Volume of vinegar 25 mL, Initial temp of vinegar 17 Celcius and final temp is 14 Celcius.

Answer 1

Explanation:

The given data is as follows.

   Density of vinegar = 1.0 g/ml

   Specific heat capacity = 4.25 $J/g ^{o}C$

   $T_{1}$ = $17 ^{o}C$,  and   $T_{2}$ = $14 ^{o}C$

Relation between enthalpy and specific heat is as follows.

                   $\Delta H = mC \Delta T$

Hence, putting the values into the above formula as follows.

          $\Delta H = mC \Delta T$

                  = $25 \times 1.0 \times 4.25 J/g ^{o}C \times -3^{o}C$          (as density = $\frac{mass}{volume}$)

                               = - 315 J

Thus, we can conclude that the enthalpy of reaction is -315 J.

As the value is negative so, it means that heat is releasing. Hence, the reaction is exothermic in nature.