Practice Enthalpy Of Reaction (δh_rxn°) (1.4.4) - Unit 5: Energetics and Thermochemistry

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6 sample questions

Question 1.
What does a negative ΔH_rxn° indicate?
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Think about whether heat is being released or absorbed.
Question 2.
What is ΔH_f°?
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Remember it involves the formation of one mole from elements.
3Question 3.
What does a positive value of ΔH_rxn° indicate?
- Exothermic Reaction
- Endothermic Reaction
- Neutral Reaction
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Consider if the reaction is taking in energy.
4Question 4.
Is Hess's Law applicable for reactions involving multiple steps?
- True
- False
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Recall if the overall change remains constant.
Question 5.
Using Hess's Law, derive the enthalpy change for the combustion of ethane using the known enthalpy values of related reactions.
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Remember to reverse or scale reactions for accurate summation.
Question 6.
Given ΔH_f° for potassium chloride (KCl), calculate the ΔH for dissolving it in water by linking it to its formation reactions.
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Consider the energy change when going from solid to ions in solution.

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