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Ch.18 - Free Energy and Thermodynamics
Tro - Chemistry: A Molecular Approach 4th Edition
Tro4th EditionChemistry: A Molecular ApproachISBN: 9780134112831당신이 사용하는 게 아니라요?교과서 변경
모든 교과서Tro 4th EditionCh.18 - Free Energy and Thermodynamics문제 62c
18장, 문제 62c

For each reaction, calculate ΔH°rxn, ΔS°rxn, and ΔG°rxn at 25 °C and state whether or not the reaction is spontaneous. If the reaction is not spontaneous, would a change in temperature make it spontaneous? If so, should the temperature be raised or lowered from 25 °C? c. N2(g) + O2(g) → 2 NO(g)

검증된 단계별 안내
1
Identify the standard enthalpy of formation (ΔH°f) for each reactant and product from a reliable source, such as a chemistry textbook or database.
Calculate the standard enthalpy change of the reaction (ΔH°rxn) using the formula: ΔH°rxn = ΣΔH°f(products) - ΣΔH°f(reactants).
Identify the standard entropy (S°) values for each reactant and product.
Calculate the standard entropy change of the reaction (ΔS°rxn) using the formula: ΔS°rxn = ΣS°(products) - ΣS°(reactants).
Calculate the standard Gibbs free energy change (ΔG°rxn) using the formula: ΔG°rxn = ΔH°rxn - TΔS°rxn, where T is the temperature in Kelvin (298 K for 25 °C). Determine spontaneity by checking if ΔG°rxn is negative. If not spontaneous, consider how temperature affects ΔG°rxn: if ΔH°rxn > 0 and ΔS°rxn > 0, increasing temperature may make the reaction spontaneous.

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주요 개념

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

Enthalpy (ΔH°rxn)

Enthalpy change (ΔH°rxn) is the heat absorbed or released during a chemical reaction at constant pressure. It indicates whether a reaction is exothermic (releases heat, ΔH° < 0) or endothermic (absorbs heat, ΔH° > 0). This value is crucial for determining the energy dynamics of the reaction and influences its spontaneity.
추천 영상:
가이드 코스
02:34
Enthalpy of Formation

Entropy (ΔS°rxn)

Entropy change (ΔS°rxn) measures the disorder or randomness of a system during a reaction. A positive ΔS° indicates an increase in disorder, while a negative ΔS° suggests a decrease. Entropy is a key factor in assessing the spontaneity of a reaction, as reactions tend to favor states of higher entropy.
추천 영상:
가이드 코스
02:46
Entropy in Thermodynamics

Gibbs Free Energy (ΔG°rxn)

Gibbs Free Energy change (ΔG°rxn) combines enthalpy and entropy to determine the spontaneity of a reaction at constant temperature and pressure. It is calculated using the equation ΔG° = ΔH° - TΔS°. A negative ΔG° indicates a spontaneous reaction, while a positive ΔG° suggests non-spontaneity. The temperature's effect on spontaneity can be analyzed through this relationship.
추천 영상:
가이드 코스
01:51
Gibbs Free Energy of Reactions
관련 실천
교과서 질문

Use standard free energies of formation to calculate ΔG° at 25 °C for each reaction in Problem 61. How do the values of ΔG° calculated this way compare to those calculated from ΔH° and ΔS°? Which of the two methods could be used to determine how ΔG° changes with temperature?

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교과서 질문

For each reaction, calculate ΔH°rxn, ΔS°rxn, and ΔG°rxn at 25 °C and state whether or not the reaction is spontaneous. If the reaction is not spontaneous, would a change in temperature make it spontaneous? If so, should the temperature be raised or lowered from 25 °C? d. N2(g) + 3 H2(g) → 2 NH3(g)

1011
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교과서 질문

For each reaction, calculate ΔH°rxn, ΔS°rxn, and ΔG°rxn at 25 °C and state whether or not the reaction is spontaneous. If the reaction is not spontaneous, would a change in temperature make it spontaneous? If so, should the temperature be raised or lowered from 25 °C? d. 2 KClO3(s) → 2 KCl(s) + 3 O2(g)

453
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교과서 질문

For each reaction, calculate ΔH°rxn, ΔS°rxn, and ΔG°rxn at 25 °C and state whether or not the reaction is spontaneous. If the reaction is not spontaneous, would a change in temperature make it spontaneous? If so, should the temperature be raised or lowered from 25 °C? a. 2 CH4(g) → C2H6(g) + H2(g)

742
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