5.4 - Hess’s Law
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Practice Questions
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Define Hess's Law.
💡 Hint: Consider how enthalpy relates to the path of a reaction.
What is a state function?
💡 Hint: Think about properties like temperature or pressure.
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Interactive Quizzes
Quick quizzes to reinforce your learning
What does Hess's Law state?
💡 Hint: Think about the relationship between path and state.
When applying Hess's Law, should the enthalpy change sign when a reaction is reversed?
💡 Hint: Consider what happens to energy in reverse reactions.
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Challenge Problems
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Determine the overall enthalpy change for a reaction given two pathways: A → B (ΔH = -45 kJ) and B → C (ΔH = +30 kJ). What is the enthalpy change for A → C?
💡 Hint: Focus on adding the enthalpies of the path taken.
Using Hess's Law, if the enthalpy changes for C to D is +50 kJ, and D to E is +30 kJ, what is the total for C to E if the path is reversed?
💡 Hint: Remember to flip the signs of any reversed processes.
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