Amole of x reacts at a constant pressure of 43.0 atm via the reaction x(g)+4y(g)→2z(g), δh∘=−75.0 kj before the reaction, the volume of the gaseous mixture was 5.00 l. after the reaction, the volume was 2.00 l. calculate the value of the total energy change, δe, in kilojoules.

The volume fraction in gasses is equal to the mole fraction.
In a reaction mixture, the molar ratio of X : Y = 1:4
Fraction of X = 1/5
Fraction of Y = 4/5
So in the 5 L reaction mix,
1 L of X and 4 L of Y
The products contain 2 L of Z
This satisfies the equation completely so we check the enthalpy of this reaction:
-75 kilojoules