Saved Bookmarks
| 1. |
Calculate the lattice energy of MgBr_(2) from the given date |
|
Answer» Solution :`Mg_((S))+Br_(2_((l)))rarrMgBr_(2_((S)))` `DeltaH_(F)^(@)=524kJmol^(-1)` Sublimation : `Mg_((s))rarrMg_((g))DeltaH_(1)^(@)=+148 "kJmol"^(-1)` Ionisation : `Mg_((s))rarrMg_((g))^(2+)+2e^(-)DeltaH_(2)^(@)=+2187 "kJmol"^(-1)` vapourisation : `Br_(2(l))rarrBr_(2(g))DeltaH_(3)^(@)=+31 "kJmol"^(-1)` Dissociation : `Br_(2(g)))rarr2Br_(2(g))DeltaH_(4)^(@)=+193 "kJmol"^(-1)` Electron AFFINITY affinity : `2Br_((g))+2e^(-)rarr2Br_((g))^(-)DeltaH_(5)^(@)=-662 "kJmol"^(-1)` Lattice enthalpy : `Mg_((g))^(2+)+2Br_((g))^(-)rarrMgBr_(2_((S)))DeltaH_(6)^(@)=?` `DeltaH_(f)^(@)=DeltaH_(1)^(@)+DeltaH_(2)^(@)+DeltaH_(3)^(@)+DeltaH_(4)^(@)+DeltaH_(5)^(@)+DeltaH_(6)^(@)` `-524=148+2187+31+193-662+DeltaH_(6)^(@)` `DeltaH_(6)^(@)=-2421kJ mol^(-1)` `Mg_((g))^(2+)+2Br_((g))^(-)rarrMgBr_(2_((s)))=DeltaH_(6)^(@)=-2421kJ mol^(-1)` By definition `MgBr_(2_((s)))rarrMg_((g))^(2+)+2Br_((g))^(-)DeltaH_(6)^(@)=-2421 kJ mol^(-1)` |
|