Respuesta :
Answer : The entropy change of the dichloromethane is 142 J/K
Explanation :
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 dichloromethane = 345 g
Molar mass of dichloromethane = 84.93 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of dichloromethane}=\frac{345g}{84.93g/mol}=4.06mol[/tex]
To calculate the entropy change for different phase at same temperature, we use the equation:
[tex]\Delta S=n\times \frac{\Delta H_{fusion}}{T}[/tex]
where,
[tex]\Delta S[/tex] = Entropy change = ?
n = moles of dichloromethane = 4.06 moles
[tex]\Delta H_{fusion}[/tex] = enthalpy of fusion = 6.2 kJ/mol = 6200 J/mol (Conversion factor: 1 kJ = 1000 J)
T = temperature of the system = [tex]-95.1^oC=[-95.1+273]K=177.9K[/tex]
Putting values in above equation, we get:
[tex]\Delta S=\frac{4.06mol\times 6200J/mol}{177.9K}\\\\\Delta S=141.495J/K\approx 142J/K[/tex]
Hence, the entropy change of the dichloromethane is 142 J/K
