Thermodynamics Question Regarding Gibbs Free Energy, Enthalpy, Entropy

Thread starter aquastor
Start date Apr 10, 2023
Tags

Energy Enthalpy Entropy Free energy Gibbs Gibbs free energy Thermodynamics

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Apr 10, 2023

aquastor

please post homework questions in the homework forum and fill the template

Hello,
is someone able to explain why these two are wrong. I am not sure how to figure out the enthalpy direction as the reaction is not changing state of matter, nor is it changing temperature.

(Please solve without calculating anything)

Thank you

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Apr 10, 2023

Borek

Mentor

Is the reaction spontaneous?

What is bond energy of a triple bond?

What is Gibbs Free Energy and why is it important in thermodynamics?

Gibbs Free Energy (G) is a thermodynamic potential that measures the maximum reversible work that may be performed by a thermodynamic system at constant temperature and pressure. It is important because it helps predict the direction of chemical reactions and phase changes. A negative change in Gibbs Free Energy indicates a spontaneous process, whereas a positive change indicates a non-spontaneous process.

How is Gibbs Free Energy related to enthalpy and entropy?

Gibbs Free Energy is related to enthalpy (H) and entropy (S) through the equation G = H - TS, where T is the temperature in Kelvin. This equation shows that the free energy of a system is determined by its enthalpy, temperature, and entropy. Changes in these variables can predict whether a process will be spontaneous.

What is the significance of the sign of the Gibbs Free Energy change (ΔG) in a reaction?

The sign of the Gibbs Free Energy change (ΔG) indicates the spontaneity of a reaction. If ΔG is negative, the reaction is spontaneous and can proceed without external input. If ΔG is positive, the reaction is non-spontaneous and requires energy input to proceed. If ΔG is zero, the system is in equilibrium, and no net change occurs.

How do enthalpy (ΔH) and entropy (ΔS) changes influence the spontaneity of a reaction?

The spontaneity of a reaction is influenced by both enthalpy (ΔH) and entropy (ΔS) changes. A reaction is more likely to be spontaneous if it releases energy (negative ΔH) and increases disorder (positive ΔS). The temperature also plays a critical role, as the TΔS term can either increase or decrease the Gibbs Free Energy, thus influencing spontaneity.

Can a reaction with a positive ΔH and a positive ΔS be spontaneous?

Yes, a reaction with a positive ΔH (endothermic) and a positive ΔS (increase in disorder) can be spontaneous if the temperature is sufficiently high. At high temperatures, the TΔS term can outweigh the ΔH term, resulting in a negative ΔG, which indicates spontaneity. This is particularly common in reactions where the increase in entropy is significant.