Calculate the change in Gibbs free energy for each of the sets of ΔHrxn, ΔSrxn, and T given in P

Calculate the change in Gibbs free energy for each of the...

Calculate the change in Gibbs free energy for each of the sets of $\Delta H_{\mathrm{rxn}}, \Delta S_{\mathrm{rxn}},$ and $T$ given in Problem $42 .$ Predict whether or not each reaction is spontaneous at the temperature indicated. (Assume that all reactants and products are in their standard states.)

Key Concepts

Gibbs Free Energy

Gibbs free energy is a thermodynamic function defined as the difference between the enthalpy change and the product of temperature and entropy change (?G = ?H - T?S). It is useful for predicting whether a reaction will proceed spontaneously under constant temperature and pressure; a negative ?G indicates a spontaneous process, while a positive ?G suggests non-spontaneity.

Enthalpy Change

Enthalpy change (?H) represents the heat absorbed or released during a reaction at constant pressure. It is a crucial factor in determining the energy profile of a reaction, where exothermic reactions (negative ?H) tend to be more favorable, though the overall spontaneity also depends on the entropy change and temperature.

Entropy Change

Entropy change (?S) measures the disorder or randomness of a system during a chemical reaction. An increase in entropy (positive ?S) generally favors spontaneity because systems naturally progress towards greater disorder; however, its effect on Gibbs free energy is scaled by the temperature.

Temperature Dependence

Temperature plays a key role in the Gibbs free energy calculation by scaling the entropy term (T?S). At higher temperatures, the contribution of the entropy change becomes more significant, potentially reversing the sign of ?G and thus altering the spontaneity of a reaction.

Reaction Spontaneity

Reaction spontaneity is determined by the sign of the Gibbs free energy change. If ?G is negative, the reaction is spontaneous; if ?G is positive, the reaction is non-spontaneous under the given conditions. This concept integrates both enthalpic and entropic contributions, with temperature as a critical factor in their relative influence.

Transcript

00:01 In the given question, we have been provided the delta h of the reactions.

00:06 Okay, we have to use the values provided in question number 42.

00:10 In this question number 44, that are delta h reaction and delta s reaction to calculate the value of delta g reaction.

00:21 Okay.

00:22 And also we have to determine whether the reaction is spontaneous or it is not.

00:27 Okay.

00:28 So these are the two questions and these two values are given to us.

00:33 Okay.

00:34 So the formula we will be using for delta g is basically delta g is delta h minus t delta s and here the temperature which is also provided should be in kelvin.

00:48 Okay.

00:49 T is the temperature.

00:50 Okay.

00:51 T here is the temperature which should be in kelvin.

00:56 So, starting with our part a, we have the value of delta h as minus 95 kilojoules.

01:04 Okay.

01:06 The temperature here is 298 kelvin while the entropy is in jule per kelvin.

01:11 So since it is in jule per kelvin, we will divide it by 1 ,000 to convert it into kilojoule per kelvin.

01:19 Okay.

01:20 So that is our entropy, which is also minus.

01:23 So this minus minus will become plus...