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: Given the following data:Calculate ΔH for the reaction On the basis of the enthalpy change, is this a useful reaction for the synthesis of ammonia?  

Solution: Given the following data:Calculate ΔH for the reaction On the basis of the enthalpy change, is this a useful reaction for the synthesis of ammonia?  

Problem

Given the following data:

Calculate ΔH for the reaction 

On the basis of the enthalpy change, is this a useful reaction for the synthesis of ammonia?  

Solution

We start solving this by setting up the equations according to the structures drawn

(1) 2NH3 (g) → N2 (g) + 3H(g)    ΔH°rxn = 92 kJ

(2) 2H2 (g) + O2 (g) → 2H2O (l)    ΔH°rxn = -484 kJ

To find the ΔHrxn of the third reaction, we need to use the Hess's Law where we have to rearrange the given equations to get the desired reaction.

View the complete written solution...