Answer: The standard heat of the solution is 85512.5 J/mol and the reaction is endothermic in nature.
Explanation:
To calculate the heat released or absorbed, we use the equation:
[tex]q=mc\Delta T[/tex]
where,
q = heat absorbed or released
m = mass of solution = (100 + 2.19) g = 102.19 g
c = specific heat capacity of water = 4.184 J/g.°C
[tex]\Delta T[/tex] = change in temperature = [tex]T_2-T_1=(29-25)^oC=4^oC[/tex]
Putting values in above equation, we get:
[tex]q=102.19g\times 4.184J/g.^oC\times 4^oC\\\\q=1710.25J[/tex]
Sign convention of heat:
When heat is absorbed, the sign of heat is taken to be positive and when heat is released, the sign of heat is taken to be negative.
To calculate the enthalpy change of the reaction, we use the equation:
[tex]\Delta H^o_{rxn}=\frac{q}{n}[/tex]
where,
[tex]q[/tex] = amount of heat absorbed = 1710.25 J
n = number of moles = 0.020 moles
[tex]\Delta H^o_{rxn}[/tex] = standard enthalpy change of the reaction
Putting values in above equation, we get:
[tex]\Delta H_{rxn}=\frac{1710.25J}{0.020mol}=85512.5J/mol[/tex]
- Exothermic reactions are defined as the reaction in which heat is released and enthalpy change of the reaction is negative.
- Endothermic reactions are defined as the reaction in which heat is absorbed and enthalpy change of the reaction is positive.
Hence, the standard heat of the solution is 85512.5 J/mol and the reaction is endothermic in nature.
