Determine the standard reaction enthalpy for the reaction: `A_(2)B_(3)(s)+3CB(g)to2A(s)+3CB_(2)(g)`
Given: (1) `2A(s)+(3)/(2)B_(2)(g)toA_(2)B_(3)(s),DeltaH^(0)=-xkJ`
(2) `CB(g)+(1)/(2)B_(2)(g) to CB_(2)(g),DeltaH^(0)=-ykJ`.

Explanation

Reversing equation (1), we get
`A_(2)B_(3)(s)to2A(s)+(3)/(2)(g),DeltaH^(0)=+xkJ` . .[3]
Multiplying equation (2) by 3, we get,
`3CB(g)+(3)/(2)(g)to3CB_(2)(g)," "DeltaH^(0)=-3y" "kJ` . . .[4]
Adding equation [3] and [4], we get,
`A_(2)B_(3)(s)+3CB(g) to 2A(s)+3CB_(2)(g),DeltaH^(0)=(x-3y)kJ`
Therefore the standard reaction enthalpy for the given reaction=(x-3y)kJ.