Respuesta :
Answer: The enthalpy change of the reaction is 239.2 kJ/mol
Explanation:
- To calculate the mass of solution, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
Density of solution = 1.0 g/mL
Volume of solution = 52.4 mL
Putting values in above equation, we get:
[tex]1.0g/mL=\frac{\text{Mass of solution}}{52.4mL}\\\\\text{Mass of solution}=(1.0g/mL\times 52.4mL)=52.4g[/tex]
- To calculate the heat absorbed we use the equation:
[tex]q=mc\Delta T[/tex]
where,
q = heat absorbed = ?
m = mass of solution = 52.4 g
c = specific heat capacity of solution = 4.18 J/g.°C
[tex]\Delta T[/tex] = change in temperature = [tex](23.9-22.0)^oC=1.9^oC[/tex]
Putting values in above equation, we get:
[tex]q=52.4g\times 4.18J/g.^oC\times 1.9^oC\\\\q=416.2J[/tex]
Heat absorbed by the solution = heat released by the reaction
- To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of zinc = 0.114 g
Molar mass of zinc = 65.4 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of zinc}=\frac{0.114g}{65.4g/mol}=0.00174mol[/tex]
- Calculating the amount of heat released per mole of zinc, we get:
[tex]\Delta H_{rxn}=\frac{\text{Heat released in the reaction}}{\text{Moles of zinc}}\\\\\Delta H_{rxn}=\frac{-416.2}{0.00174}=239195.4J/mol=239.2kJ/mol[/tex]
Conversion factor: 1 kJ = 1000 J
Hence, the enthalpy change of the reaction is 239.2 kJ/mol
