Respuesta :
Answer:
The lattice energy of magnesium sulfide is -3,406 kJ/mol.
Explanation:
[tex] Mg(s)\rightarrow Mg(g) ,\Delta H^o_{1} = 148 kJ/mol[/tex]..[1]
[tex]Mg(g) \rightarrow Mg^{2+}(g) + 2e^- ,\Delta H^o_{2} = 2,186 kJ/mol [/tex]..[2]
[tex]S_8(s) \rightarrow 8S(g) ,\Delta H^o_{3} = 2,232 kJ/mol [/tex]..[3]
[tex]S(g) + 2e^- \rightarrow S^{2-}(g),\Delta H^o_{4} = 450 kJ/mol [/tex]..[4]
[tex]8Mg(s) + S_8(s) \rightarrow 8MgS(s),\Delta H^o_{5} = -2,744 kJ/mol [/tex]..[5]
[tex]MgS(s)\rightarrow Mg^{2+}(g) + S^{2-}(g),\Delta H^o_{lattice}=?[/tex]..[6]
By using Hess's law:
[tex][6]=\frac{1}{8}\times [5]-[1]-[2]-\frac{1}{8}\times [3]-[4][/tex]
[tex]\Delta H^o_{lattice} =[/tex]
[tex]=\frac{1}{8}\times \Delta H^o_{5}-\Delta H^o_{1}-\Delta H^o_{2}-\frac{1}{8}\times \Delta H^o_{3}- \Delta H^o_{4}[/tex]
[tex]\Delta H^o_{lattice}=\frac{1}{8}\times (-2,744 kJ/mol)-148 kJ/mol-2,186 kJ/mol-\frac{1}{8}\times 2,232 kJ/mol-450 kJ/mol[/tex]
[tex]\Delta H^o_{lattice}=-3406 kJ/mol[/tex]
The lattice energy of magnesium sulfide is -3,406 kJ/mol.
