Given the values of ΔH°_rxn, ΔS°_rxn, and T, determine ΔS_univ and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) a. ΔH°_rxn = +115 kJ; ΔS°_rxn = -263 J/K; T = 298 K

검증된 단계별 안내

1. The first step is to convert the enthalpy change (ΔH°_rxn) from kJ to J, because the entropy change (ΔS°_rxn) is given in J/K. To do this, multiply the given ΔH°_rxn by 1000. So, ΔH°_rxn = +115 kJ * 1000 = +115000 J.

2. Next, calculate the change in entropy of the system (ΔS_sys) using the formula ΔS_sys = ΔH°_rxn/T. Substitute the values of ΔH°_rxn and T into the formula to get the value of ΔS_sys.

3. The change in entropy of the universe (ΔS_univ) is given by the formula ΔS_univ = ΔS_sys + ΔS°_rxn. Substitute the values of ΔS_sys and ΔS°_rxn into the formula to get the value of ΔS_univ.

4. If ΔS_univ is greater than zero, the reaction is spontaneous. If ΔS_univ is less than zero, the reaction is non-spontaneous. If ΔS_univ equals zero, the reaction is at equilibrium.

5. Use the value of ΔS_univ obtained in step 3 to determine whether the reaction is spontaneous or not.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.

영상 길이:

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.

Entropy (ΔS)

Entropy (ΔS) is a measure of the disorder or randomness in a system. In the context of a chemical reaction, it quantifies the change in disorder between reactants and products. A positive ΔS indicates an increase in disorder, which generally favors spontaneity, while a negative ΔS suggests a decrease in disorder, which can hinder spontaneity.

Enthalpy (ΔH)

Enthalpy (ΔH) is a measure of the total heat content of a system and reflects the energy required to break and form bonds during a chemical reaction. A positive ΔH indicates that the reaction is endothermic, absorbing heat from the surroundings, while a negative ΔH indicates an exothermic reaction, releasing heat. The sign and magnitude of ΔH influence the overall spontaneity of the reaction when combined with entropy changes.

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 = +115 kJ; ΔS°rxn = -263 J/K; T = 298 K