Respuesta :
Explanation:
It is known that,
   No. of moles = Molarity × Volume
So, we will calculate the moles of [tex]H_{3}PO_{4}[/tex] as follows.
     No. of moles = [tex]0.227 \times 0.055 L[/tex]
                = 0.0125 mol
Now, the moles of KOH are as follows.
    No. of moles = [tex]0.680 \times 0.055 L[/tex]
                = 0.0374 mol
And, [tex]3 \times \text{moles of} H_{3}PO_{4}[/tex] = [tex]3 \times 0.0125[/tex]
               = 0.0375 mol
Now, the balanced reaction equation is as follows.
   [tex]H_{3}PO_{4}(aq) + 3KOH(aq) \rightarrow 3H_{2}O(l) + K_{3}PO_{4}(aq) + 173.2 kJ[/tex]
This means 1 mole of [tex]H_{3}PO_{4}[/tex] produces 173.2 kJ of heat. And, the amount of heat produced by 0.0125 moles of [tex]H_{3}PO_{4}[/tex] is as follows.
     M = [tex]\frac{0.0125 mol \times 173.2 kJ}{1}[/tex]
       = 2.165 kJ
Total volume of the solution = (55.0 + 55.0) ml
                        = 110 ml
Density of the solution = 1.13 g/ml
Mass of the solution = Volume × Density
                 = [tex]110 ml \times 1.13 g/ml[/tex]
                 = 124.3 g
Specific heat = 3.78 [tex]J/g^{o}C[/tex]
Now, we will calculate the final temperature as follows.
       q = [tex]mC \times \Delta T[/tex]
     2165 J = [tex]124.3 \times 3.78 \times (T - 22.62)^{o}C[/tex]
    2165 - 469.854 = [tex]T - 22.62^{o}C[/tex]
      17.417 = [tex]T - 22.62^{o}C[/tex]
        T = [tex]40.04^{o}C[/tex]
Thus, we can conclude that final temperature of the solution is [tex]40.04^{o}C[/tex].
