Enthalpy of Formation Worksheet
Grade 11 Chemistry worksheet covering the concept of enthalpy of formation, Hess's Law, and calculations involving standard enthalpies.
Includes
Standards
Enthalpy of Formation
Name:
Date:
Score:
Read each question carefully and provide your answers in the space provided. Show all your work for calculation questions.
1. Which of the following statements best defines the standard enthalpy of formation (ΔH°f)?
The enthalpy change when one mole of a compound is formed from its elements in their standard states.
The enthalpy change when a compound is decomposed into its elements.
The total enthalpy of a compound at standard conditions.
The heat released during a combustion reaction.
2. The standard enthalpy of formation for any element in its most stable allotropic form at standard conditions is defined as .
3. Hess's Law states that the total enthalpy change for a reaction is of the pathway taken.
4. Explain why the standard enthalpy of formation is a useful concept in thermochemistry.
5. An exothermic reaction has a positive enthalpy change (ΔH > 0).
True
False
6. Using the following standard enthalpies of formation, calculate the enthalpy change (ΔH°) for the reaction: 2SO₂(g) + O₂(g) → 2SO₃(g)
Given:
ΔH°f [SO₂(g)] = -296.8 kJ/mol
ΔH°f [SO₃(g)] = -395.7 kJ/mol
7. Analyze the energy diagram below and determine if the reaction represented is exothermic or endothermic. Explain your reasoning.
