Practice Using Hess’s Law With Multiple Steps (2.2.3) - Unit 5: Energetics and Thermochemistry

Practice: Using Hess’s Law with Multiple Steps

Lesson 2.2.3Unit 5: Energetics and Thermochemistry

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9 questions

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6 sample questions

Question 1.
What does Hess's Law state?
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Think of it in terms of total energy changes.
Question 2.
Can we measure ΔH for a reaction directly?
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Consider how we can apply known values in calculating other reactions.
3Question 3.
What does Hess's Law allow us to do?
- Find ΔH for unknown reactions
- Measure temperature changes
- Identify reactants in a reaction
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Think about how we can use known values to derive new properties.
4Question 4.
True or False: Hess's Law states that the path taken in a chemical reaction affects the total energy change.
- True
- False
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Consider the main idea behind Hess's Law.
Question 5.
Using Hess’s Law, calculate the enthalpy change for the following target reaction: N₂(g) + 3H₂(g) → 2NH₃(g) from known ΔH values. Use the formation enthalpy of NH₃ and others as necessary.
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Make sure to balance and reverse reactions as needed for the final calculations.
Question 6.
How would you determine ΔH for the reaction 2 CO(g) + O₂(g) → 2 CO₂(g) using formation enthalpies? Write out the equations and the steps you take.
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Ensure you understand how to balance and apply known values to formulate your solution.

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