Use the data in Appendix B to tell which of the following compounds are thermodynamically stable with respect to their constituent elements at 25 °C: (a) BaCO3(s) (b) HBr(g) (c) N2O(g) (d) C2H4(g).

Name: Chemistry
Author: McMurry
ISBN: 9781292336145

Guida verificata passo dopo passo

Step 1: Understand the concept of thermodynamic stability. A compound is thermodynamically stable with respect to its constituent elements if its standard Gibbs free energy of formation (ΔG_f^°) is negative at 25 °C.

Step 2: Locate the standard Gibbs free energy of formation (ΔG_f^°) values for each compound from Appendix B. These values are typically given in units of kJ/mol.

Step 3: For each compound, check the sign of the ΔG_f^° value. If ΔG_f^° is negative, the compound is thermodynamically stable with respect to its constituent elements at 25 °C.

Step 4: Analyze the data for each compound: (a) BaCO3(s), (b) HBr(g), (c) N2O(g), and (d) C2H4(g). Compare their ΔG_f^° values to determine their stability.

Step 5: Conclude which compounds are thermodynamically stable by identifying those with negative ΔG_f^° values.

Concetti chiave

Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.

Thermodynamic Stability

Thermodynamic stability refers to the condition of a compound being at a lower energy state compared to its constituent elements under specified conditions, such as temperature and pressure. A thermodynamically stable compound will not spontaneously decompose into its elements, indicating that the formation of the compound is favored energetically.

Video consigliato:

Percorso guidato

01:18

First Law of Thermodynamics

Standard State and Standard Enthalpy of Formation

The standard state of a substance is its most stable form at 1 bar of pressure and a specified temperature, typically 25 °C. The standard enthalpy of formation is the change in enthalpy when one mole of a compound is formed from its elements in their standard states. This value helps determine the stability of a compound by comparing the energy of the compound to the energy of its constituent elements.

Video consigliato:

Percorso guidato

02:34

Enthalpy of Formation

Gibbs Free Energy

Gibbs free energy (G) is a thermodynamic potential that measures the maximum reversible work obtainable from a thermodynamic system at constant temperature and pressure. A negative change in Gibbs free energy (ΔG) during a reaction indicates that the products are more stable than the reactants, thus favoring the formation of the compound from its elements.

Video consigliato:

Percorso guidato