Practice Enthalpy of Formation (ΔH_f°) - 1.4.1 | Unit 5: Energetics and Thermochemistry | IB Grade 11: Chemistry
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Enthalpy of Formation (ΔH_f°)

1.4.1 - Enthalpy of Formation (ΔH_f°)

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Practice Questions

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Question 1 Easy

What is the standard enthalpy of formation for elements in their standard state?

💡 Hint: Remember the definition of standard enthalpy of formation.

Question 2 Easy

Write the reaction equation for the formation of water.

💡 Hint: Think of what elements combine to form water.

4 more questions available

Interactive Quizzes

Quick quizzes to reinforce your learning

Question 1

What is the enthalpy of formation of elements in their standard state?

0 kJ/mol
100 kJ/mol
Negative value

💡 Hint: Think about the baseline for enthalpy.

Question 2

Is the enthalpy of formation for water negative or positive?

True
False

💡 Hint: Recall what happens during process energy release.

1 more question available

Challenge Problems

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Challenge 1 Hard

Acetylene (C₂H₂) undergoes combustion to form CO₂ and H₂O. Given ΔH_f° is -1,203 kJ/mol for C₂H₂, -393.5 kJ/mol for CO₂, and -285.8 kJ/mol for H₂O, calculate the ΔH for the combustion reaction.

💡 Hint: Balance the reaction before plugging in enthalpy values.

Challenge 2 Hard

Use Hess's law to find ΔH for the reaction 2NH₃(g) + 3O₂(g) → N₂(g) + 3H₂O(l). Given provided formation values, calculate and show steps.

💡 Hint: Break it down into multiple known reactions to build it out stepwise.

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