AP Chemistryeasymcq1 pt
Use Hess's law: A → B (ΔH = +30 kJ) and B → C (ΔH = −50 kJ). What is ΔH for A → C?
A.−20 kJ
B.+80 kJ
C.−80 kJ
D.+20 kJ
Explanation
Core Concept
Enthalpy is a state function, so pathway steps sum: +30 + (−50) = −20 kJ. A → C is exothermic even though the first step absorbed heat.
Correct Answer
A−20 kJ
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