Skip to main content
Ch.19 - Free Energy & Thermodynamics
Tro - Chemistry: A Molecular Approach 6th Edition
Tro6th EditionChemistry: A Molecular ApproachISBN: 9780137832217당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Tro 6th EditionCh.19 - Free Energy & Thermodynamics문제 43a
19장, 문제 43a

Given the values of ΔH°rxn, ΔS°rxn, and T, determine ΔSuniv and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) a. ΔH°rxn = +135 kJ; ΔS°rxn = -282 J/K; T = 298 K

검증된 단계별 안내
1
Identify the formula for the change in entropy of the universe: \( \Delta S_{univ} = \Delta S_{sys} + \Delta S_{surr} \).
Recognize that \( \Delta S_{sys} \) is given as \( \Delta S^{\circ}_{rxn} = -282 \text{ J/K} \).
Calculate \( \Delta S_{surr} \) using the formula \( \Delta S_{surr} = -\frac{\Delta H^{\circ}_{rxn}}{T} \). Convert \( \Delta H^{\circ}_{rxn} \) from kJ to J by multiplying by 1000.
Substitute the values into the formula: \( \Delta S_{surr} = -\frac{135,000 \text{ J}}{298 \text{ K}} \).
Add \( \Delta S_{sys} \) and \( \Delta S_{surr} \) to find \( \Delta S_{univ} \). If \( \Delta S_{univ} > 0 \), the reaction is spontaneous; if \( \Delta S_{univ} < 0 \), it is non-spontaneous.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
4m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Gibbs Free Energy

Gibbs Free Energy (G) is a thermodynamic potential that helps predict the spontaneity of a reaction at constant temperature and pressure. It is calculated using the equation ΔG = ΔH - TΔS, where ΔH is the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy. A negative ΔG indicates a spontaneous reaction, while a positive ΔG suggests non-spontaneity.
추천 영상:
가이드 코스
01:51
Gibbs Free Energy of Reactions

Entropy (ΔS)

Entropy (ΔS) is a measure of the disorder or randomness in a system. In the context of chemical reactions, a positive change in entropy (ΔS > 0) typically favors spontaneity, as systems tend to evolve towards greater disorder. Conversely, a negative change in entropy (ΔS < 0) indicates a decrease in disorder, which can hinder spontaneity depending on the enthalpy change.
추천 영상:
가이드 코스
02:46
Entropy in Thermodynamics

Enthalpy (ΔH)

Enthalpy (ΔH) is a measure of the total heat content of a system and reflects the energy absorbed or released during a reaction. A positive ΔH indicates that the reaction is endothermic (absorbs heat), while a negative ΔH indicates an exothermic reaction (releases heat). The sign and magnitude of ΔH, in conjunction with ΔS, are crucial for determining the overall spontaneity of a reaction through the Gibbs Free Energy equation.
추천 영상:
가이드 코스
02:34
Enthalpy of Formation
관련 실천
교과서 질문

Without doing any calculations, determine the signs of ΔSsys and ΔSsurr for each chemical reaction. In addition, predict under what temperatures (all temperatures, low temperatures, or high temperatures), if any, the reaction is spontaneous. c. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) ΔH°rxn = -2044 kJ

교과서 질문

Given the values of ΔH°rxn, ΔS°rxn, and T, determine ΔSuniv and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) c. ΔH°rxn = +75 kJ; ΔS°rxn = -127 J/K; T = 298 K

교과서 질문

Calculate ΔSsurr at the indicated temperature for each reaction. d. ΔH°rxn = +114 kJ; 77 K

1273
views
교과서 질문

Given the values of ΔH°rxn, ΔS°rxn, and T, determine ΔSuniv and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) c. ΔH°rxn = -135 kJ; ΔS°rxn = -282 J>K; T = 298 K

교과서 질문

Without doing any calculations, determine the signs of ΔSsys and ΔS surr for each chemical reaction. In addition, predict under what temperatures (all temperatures, low temperatures, or high temperatures), if any, the reaction is spontaneous. a. C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g) ΔH°rxn = -2044 kJ

1
views
교과서 질문

Given the values of ΔH°rxn, ΔS°rxn, and T, determine ΔSuniv and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) a. ΔH°rxn = -75 kJ; ΔS°rxn = -127 J/K; T = 298 K