For the solvation of borax in water, would delta Ssys increase or decrease in the reaction?
I was thinking that since delta H is positive then delta Ssys is negative but I am not completely sure.
The ions making up borax have much more freedom of movement in solution. Also, the chemical species in solution are more mixed up than they would be in separate phases. What would that do to the total entropy of system?
So would it be positive then since the a positive S means more disorder?
I gave you the background information needed to draw your own conclusions.
Yes. It would be positive. Given the formula deltaG= delta(H)-Tdelta(S), a positive H minus Tdelta(S) with a low temperature has the ability to make delta G negative, but the greater the temperature, the more negative delta G becomes. The more negative delta G is, the more spontaneous the reaction is. If delta S was negative then delta G would only get larger, and therefore less spontaneous. Since Borax is represented by the following reaction, we know that it is spontaneous.
Na2B4O7·10H2O(s) <-> 2Na+(aq)+ B4O5(OH)4^2-(aq) + H20(l)
You'll have less entropy in a solid, so the reaction will be spontaneous in the forward direction.
To determine whether the entropy change (ΔSsys) for the solvation of borax in water would increase or decrease, we need to consider the overall process of solvation.
In the case of solvation, borax dissolves in water, forming hydrated borate ions. This process involves breaking the strong intermolecular forces between borax molecules and the formation of new solute-solvent interactions.
First, let's analyze the enthalpy change (ΔH) of the reaction. You correctly mentioned that ΔH is positive, indicating an endothermic reaction. This means that energy is absorbed from the surroundings for the solvation process to occur.
Now, let's focus on the entropy change (ΔS) in the system. The system consists of the borax solute and water solvent. When borax dissolves in water, the number of particles (molecules or ions) in the system increases. Additionally, there is an increase in the disorder of the system since the random arrangement of water molecules around the solute is more entropically favorable compared to the organized crystal lattice of the solid borax.
Considering these factors, the entropy change (ΔSsys) for the solvation of borax in water is expected to increase. The dissolution of borax leads to an increase in the randomness and disorder of the system, resulting in a positive ΔSsys.
To summarize, although ΔH is positive (indicating an endothermic process), ΔSsys is also positive in the case of the solvation of borax in water.