Practice Questions
Test your understanding with targeted questions related to the topic.
Question 1
Easy
What does Hess's Law state?
๐ก Hint: Think of a journey taken by different routes.
Question 2
Easy
What happens to the enthalpy change when we reverse a reaction?
๐ก Hint: Review the direction of energy flow.
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Interactive Quizzes
Engage in quick quizzes to reinforce what you've learned and check your comprehension.
Question 1
What is Hess's Law?
- Energy change is always the same regardless of the path taken.
- Energy changes depend on the path taken.
๐ก Hint: Recall the main principle of Hess's Law.
Question 2
True or False: When reversing a reaction, you must also reverse the sign of the enthalpy change.
- True
- False
๐ก Hint: Think about how energy flows with direction.
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Challenge Problems
Push your limits with challenges.
Question 1
Calculate the ฮH for this series of reactions involving CO2: C(s) + O2(g) โ CO2(g) ฮH1 = -393.5 kJ, CO(g) + ยฝO2(g) โ CO2(g) ฮH2 = -283.0 kJ. How does reversing reactions affect ฮH?
๐ก Hint: Think carefully about how reversing a reaction changes the sign of the enthalpy.
Question 2
Apply Hess's Law to find the total enthalpy change for this reaction: N2(g) + 3H2(g) โ 2NH3(g). Use the given reactions: N2(g) + 2H2(g) โ 2NH2(g) ฮH = -100 kJ, NH2 + H2 โ NH3 ฮH = -50 kJ. What's ฮH?
๐ก Hint: Manipulate the equations carefully; how do the signs play a role?
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