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Hess's law

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Problem

The table below contains information about four different reactions, labeled W, X, Y, and Z.
ReactionEquationΔH°(kJ/molrxn)
WNA2(g)+3HA2(g)2NHA3(g)92
X2HA2(g)+OA2(g)2HA2O(l)572
YNA2(g)+2OA2(g)2NOA2(g)66
Z2NHA3(g)+4HA2O(l)2NOA2(g)+7HA2(g)?
Using the information above, determine the value of ΔH°rxn for reaction Z.
Write your answer to the ones place.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3/5
  • a simplified improper fraction, like 7/4
  • a mixed number, like 1 3/4
  • an exact decimal, like 0.75
  • a multiple of pi, like 12 pi or 2/3 pi
kJ/molrxn
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