Ch. 17 - Chemical ThermodynamicsWorksheetSee 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: For the following reaction, ΔH rxn = −120 kJ / mol-rxn and ΔS rxn = −150 J / mol-rxn•K:2NO(g) + O2(g) → 2NO2(g)At what temperatures will this reaction be spontaneous?Note: Remember that we can assume

Problem

For the following reaction, ΔH rxn = −120 kJ / mol-rxn and ΔS rxn = −150 J / mol-rxn•K:

2NO(g) + O2(g) → 2NO2(g)

At what temperatures will this reaction be spontaneous?

Note: Remember that we can assume that the ΔH and ΔS values are approximately independent of temperature.

Choose 1 answer:

a. The reaction is never spontaneous, no matter what the temperature.

b. The reaction is spontaneous when T < 800 K.

c. The reaction is spontaneous when T > 800 K.

d. The reaction is spontaneous at all temperatures.

Solution

We are asked for the temperatures at which this reaction would be spontaneous.

First, we look at the Punnet square below to know if we even have to solve or not. 

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