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Hey everyone I was doing an MCAT of the day questions and ran across this question which doesn't make that much sense to me. I was hoping someone could shed some light in the answer. The answer they included talked about entropy, but since the temperature goes to zero, then entropy should be zero.
Q: A solute is placed inside of a solvent. It is noted that the solute has very strong attractive forces with the solvent. In a plot of Gibbs free energy versus temperature, what can be inferred about the y-intercept of the graph of the pure solvent and the solvent with solute?
A: The pure solvent will intersect the y-intercept higher than the impure solvent.
Their explanation:
The impure solvent has attractive forces with the solute, therefore it can be inferred that the solvent decreases the entropy of the solute. This occurs because the attractive forces order the solvent more than if they were in the pure solution. At the y-intercept, temperature is zero, therefore having a lower entropy is the same as having a lower G (Gibbs free energy), therefore the pure solvent intersects the y-intercept higher than the impure solvent.
Q: A solute is placed inside of a solvent. It is noted that the solute has very strong attractive forces with the solvent. In a plot of Gibbs free energy versus temperature, what can be inferred about the y-intercept of the graph of the pure solvent and the solvent with solute?
A: The pure solvent will intersect the y-intercept higher than the impure solvent.
Their explanation:
The impure solvent has attractive forces with the solute, therefore it can be inferred that the solvent decreases the entropy of the solute. This occurs because the attractive forces order the solvent more than if they were in the pure solution. At the y-intercept, temperature is zero, therefore having a lower entropy is the same as having a lower G (Gibbs free energy), therefore the pure solvent intersects the y-intercept higher than the impure solvent.
