Skip to main content
Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium
McMurry - Chemistry 8th Edition
McMurry8th EditionChemistryISBN: 9781292336145Non è quello che usi tu?Cambia libro di testo
Tutti i libri di testoMcMurry 8th EditionCh.18 - Thermodynamics: Entropy, Free Energy & EquilibriumProblema 78a
Capitolo 18, Problema 78a

For the vaporization of benzene, ∆Hvap = 30.7 kJ/mol and ∆Svap = 87.0 J/(K*mol). Calculate ∆Ssurr and ∆Stotal at: (a) 70 °C

Guida verificata passo dopo passo
1
Convert the temperature from Celsius to Kelvin by adding 273.15 to the given temperature: T(K) = 70 + 273.15.
Calculate the entropy change of the surroundings (\( \Delta S_{surr} \)) using the formula: \( \Delta S_{surr} = -\frac{\Delta H_{vap}}{T} \). Make sure to convert \( \Delta H_{vap} \) from kJ/mol to J/mol by multiplying by 1000.
Substitute the values into the formula: \( \Delta S_{surr} = -\frac{30.7 \times 1000}{T(K)} \).
Calculate the total entropy change (\( \Delta S_{total} \)) using the formula: \( \Delta S_{total} = \Delta S_{vap} + \Delta S_{surr} \).
Substitute the given \( \Delta S_{vap} \) and the calculated \( \Delta S_{surr} \) into the formula to find \( \Delta S_{total} \).

Risposta video verificata per un problema simile:

Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
3m

Concetti chiave

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

Gibbs Free Energy and Spontaneity

Gibbs Free Energy (G) is a thermodynamic potential that helps predict whether a process will occur spontaneously at constant temperature and pressure. The change in Gibbs Free Energy (∆G) is calculated using the equation ∆G = ∆H - T∆S, where ∆H is the change in enthalpy, T is the temperature in Kelvin, and ∆S is the change in entropy. A negative ∆G indicates a spontaneous process.
Video consigliato:
Percorso guidato
01:51
Gibbs Free Energy of Reactions

Entropy Change of the Surroundings (∆S_surr)

The entropy change of the surroundings (∆S_surr) during a process can be calculated using the formula ∆S_surr = -∆H/T, where ∆H is the enthalpy change of the system and T is the temperature in Kelvin. This relationship shows how the heat exchanged with the surroundings affects the disorder or randomness of the surroundings, which is crucial for understanding the overall entropy changes in a thermodynamic process.
Video consigliato:
Percorso guidato
00:53
Entropy of Surroundings Formula

Total Entropy Change (∆S_total)

The total entropy change (∆S_total) of a system and its surroundings is the sum of the entropy change of the system (∆S_sys) and the entropy change of the surroundings (∆S_surr). It is given by the equation ∆S_total = ∆S_sys + ∆S_surr. For a process to be spontaneous, ∆S_total must be greater than zero, indicating an overall increase in disorder in the universe.
Video consigliato:
Percorso guidato
01:23
Total Entropy Example
Pratica correlata
Domanda del libro di testo

Phosphorus pentachloride forms from phosphorus trichloride and chlorine:

(a) Use data in Appendix B to calculate ∆Ssys, ∆Ssurr, and ∆Stotal for this reaction. Is the reaction spontaneous under standard-state conditions at 25 °C?

573
views
Domanda del libro di testo

For the vaporization of benzene, ∆Hvap = 30.7 kJ/mol and ∆Svap = 87.0 J/(K*mol). Does benzene boil at 70 °C and 1 atm pressure? Calculate the normal boiling point of benzene.

906
views
Domanda del libro di testo
Elemental sulfur is formed by the reaction of zinc sulfide with oxygen: (b) At what temperature, if any, the reaction will become nonspontaneous?
411
views
Domanda del libro di testo
For the melting point of sodium chloride, ΔHfusion = 28.16 kJ/mol and ΔSfusion = 26.22 J/(K·mol). Does NaCl melt at 1100 K? Calculate the melting point of NaCl.
1368
views
Domanda del libro di testo

Phosphorus pentachloride forms from phosphorus trichloride and chlorine: PCl3(g) + Cl2(g) → PCl5(g) (b) Estimate the temperature at which the reaction will become nonspontaneous.

617
views
Domanda del libro di testo
The entropy change for a certain nonspontaneous reaction at 50 °C is 104 J/K. (a) Is the reaction endothermic or exothermic? (b) What is the minimum value of ∆H (in kJ) for the reaction?
531
views