I2(g) + Cl2(g)2ICl(g) Using standard thermodynamic data at 298K, calculate the entropy change for the surroundings when 1.62 moles of I2(g) react at standard conditions. S°surroundings = J/K

Respuesta :

Answer:

The change in entropy of the surrounding is -146.11 J/K.

Explanation:

Enthalpy of formation of iodine gas = [tex]\Delta H_f_{(I_2)}=62.438 kJ/mol[/tex]

Enthalpy of formation of chlorine gas = [tex]\Delta H_f_{(Cl_2)}=0 kJ/mol[/tex]

Enthalpy of formation of ICl gas = [tex]\Delta H_f_{(ICl)}=17.78 kJ/mol[/tex]

The equation used to calculate enthalpy change is of a reaction is:  

[tex]\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)][/tex]

For the given chemical reaction:

[tex]I_2(g)+Cl_2(g)\rightarrow 2ICl(g),\Delta H_{rxn}=?[/tex]

The equation for the enthalpy change of the above reaction is:

[tex]\Delta H_{rxn}=[(2\times \Delta H_f_{(ICl)})]-[(1\times \Delta H_f_{(I_2)})+(1\times \Delta H_f_{(Cl_2)})][/tex]

[tex]=[2\times 17.78 kJ/mol]-[1\times 0 kJ/mol+1\times 62.436 kJ/mol]=-26.878 kJ/mol[/tex]

Enthaply change when 1.62 moles of iodine gas recast:

[tex]\Delta H= \Delta H_{rxn}\times 1.62 mol=(-26.878 kJ/mol)\times 1.62 mol=-43.542 kJ[/tex]

Entropy of the surrounding = [tex]\Delta S^o_{surr}=\frac{\Delta H}{T}[/tex]

[tex]=\frac{-43.542 kJ}{298 K}=\frac{-43,542 J}{298 K}=-146.11 J/K[/tex]

1 kJ = 1000 J

The change in entropy of the surrounding is -146.11 J/K.