Calculate standard internal energy change for OF _ 2( ~g ) + H ₂ O _ ( g ) 2 HF _ ( g ) + O _ 2( ~g ) at 300 K, if _ f H ^ of OF _ 2( ~g ) , H ₂ O _ ( g ) and HF _ ( g ) are 20, -250 and -270 ~kJ ~mol ⁻¹ respectively. [ R =8.314 ~J ~K ⁻¹ ~mol ⁻¹ ]

Step-by-step solution

aligned _ f H ^ & = _ f H ^ of product - _ f H ^ of Reactants & =[(2 -270+0)-(20-250)] kJ mol ⁻¹ & =-310 10^3 ~J ~mol ⁻¹ H ^ & = U ^ + n _ g RT U ^ & = H ^ - ng _ g RT & =-310 10^3 ~J ~mol ⁻¹-(3-2) & 8.314 ~J ~K ~mol ⁻¹ 300 ~K U ^ & =-307.50 ~kJ aligned