Practice Statement of Hess’s Law - 2.2.1 | Unit 5: Energetics and Thermochemistry | IB Grade 11: Chemistry
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Statement of Hess’s Law

2.2.1 - Statement of Hess’s Law

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Practice Questions

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Question 1 Easy

What does Hess's Law state?

💡 Hint: Think about the enthalpy being a state function.

Question 2 Easy

What is a state function?

💡 Hint: Does it depend on how you got there?

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

Question 1

What does Hess's Law indicate about total enthalpy change?

Is path-dependent.
Is path-independent.
Depends only on reactants.

💡 Hint: Consider if the steps matter.

Question 2

True or False: Hess's Law can be utilized to calculate the enthalpy changes from known reactions.

True
False

💡 Hint: Think about combining reactions.

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Challenge Problems

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Challenge 1 Hard

Calculate the ΔH for the reaction: 2 H₂(g) + O₂(g) → 2 H₂O(l) using Hess's Law if you know the standard enthalpy of formation for H₂O is -285.8 kJ/mol.

💡 Hint: Remember to account for each mole of product formed.

Challenge 2 Hard

If the formation enthalpy of CO(g) is -110.5 kJ/mol and that for O₂ is zero, what would be the total ΔH for the reaction: C(s) + O₂(g) → CO(g) using Hess's Law?

💡 Hint: Use the fact that elemental states have zero formation enthalpy.

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Reference links

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