Ch.6 - Thermochemistry WorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: Calculate ΔHrxn for each of the following reactions using the data in Appendix 4:4Na (s) + O2 (g) → 2Na2O (s)2Na (s) + 2H2O (l) → 2NaOH (aq) + H2 (g)2Na (s) + CO2 (g) → Na2O (s) + CO (g)Explain why a

Solution: Calculate ΔHrxn for each of the following reactions using the data in Appendix 4:4Na (s) + O2 (g) → 2Na2O (s)2Na (s) + 2H2O (l) → 2NaOH (aq) + H2 (g)2Na (s) + CO2 (g) → Na2O (s) + CO (g)Explain why a

Problem

Calculate ΔHrxn for each of the following reactions using the data in Appendix 4:

4Na (s) + O2 (g) → 2Na2O (s)

2Na (s) + 2H2O (l) → 2NaOH (aq) + H2 (g)

2Na (s) + CO2 (g) → Na2O (s) + CO (g)

Explain why a water or carbon dioxide fire extinguisher might not be effective in putting out a sodium fire.

Solution

Below is a compiled list of the enthalpy of formation values of each species involved in the reactions: 

To solve for ΔHo we use the formula below: 

Note: n and m in the equation are just the coefficients in the reaction. 

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