J.R. S. answered 03/07/20
Ph.D. University Professor with 10+ years Tutoring Experience
Hess Law....
4XY3 ==> 2X2 + 6Y2 ΔH = +640 kK
6Y2 + 3Z2. ==> 6Y2Z ΔH = +870 kJ
2X2 + 4Z2 ==> 4XZ2 ΔH = +340 kJ
Add all equationto get tge desired target equation, and add the ΔH values to get 1850 kJ