Saved Bookmarks
| 1. |
(i)State the law of mass action. (ii) Deduce the vant equation. |
|
Answer» Solution :(i) The law state that .At any instant ,the RATE of chemical recation at a given temp is DIRECTLY proportional to the active masses of the reactants at the instant. (ii) Vant Hoff EQUATION, This equation gives the quantitative temp depends of EQUILBRIUM constant K. The relation between standard free energy change `DeltaG^(@)` and equilbrium constant is `DeltaG^(@)=-RTInK` We know rhat, `DeltaG^(@)=DeltaH^(@)-TDeltaS^(@)` Substituting (1) in equation (2) 1-RTInK`=DeltaH^(@)-TDeltaS^(@)` Rearranging, `InK=(-DeltaH^(@))/(RT)+(DeltaS^(@))/(R)` Diffrentiating equation (3) with respect to Temp `(d(InK))/(dT)=(DeltaH^(@))/(RT^(@))` Equation (4) is known as defferential form of van.t Hoff equation on intergrating the equation 4, between `T_(1) and T_(2)` with their resoective equilibrium constant `K_(1) and K_(2)` `int_(K_(1))^(K_(2))d(InK)=(DeltaH(@))/(R)int_(T_(1))^(T_(2))(dT)/(T^(2))` `[InK]_(K_(1))^(K_(2))=(DeltaH(@))/(R)[-(1)/(T)]_(T_(1))^(T_(2))` `InK_(2)-InK_(1)=(DeltaH(@))/(R)[-(1)/(T_(2))+(1)/(T_(1))]` In`(K_(2))/(K_(1))=(DeltaH(@))/(R)[(T_(2)-T_(1))/(T_(2)T_(1))]` Log`(K_(2))/(K_(1))=(DeltaH(@))/(2.303R)[(T_(2)-T_(1))/(T_(2)T_(1))]` Equation (5) is known as integrated form of van.t Hpff equation. |
|