4.2 - Hess's Law
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Practice Questions
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What does Hess's Law state?
💡 Hint: Think about steps in a journey.
What happens to ΔH when you reverse a reaction?
💡 Hint: Consider it like undoing something!
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Interactive Quizzes
Quick quizzes to reinforce your learning
Hess's Law states that the total enthalpy change is dependent on:
💡 Hint: Remember, it's all about the start and finish!
True or False: The enthalpy change of a reaction is always positive.
💡 Hint: Think about heat absorption and release.
1 more question available
Challenge Problems
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Given the enthalpy changes for the following reactions: 1) C + O₂ → CO₂, ΔH = -393.5 kJ; 2) CO + ½O₂ → CO₂, ΔH = -283.0 kJ, calculate the ΔH for the reaction C + ½O₂ → CO.
💡 Hint: Pay close attention to the coefficients and how they affect enthalpy.
If you find the ΔH for the formation of a compound from its elements is unknown, how would you use Hess's Law to find it?
💡 Hint: Look for routes that include your desired reactants and products.
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