Hi, Just have follow up questions to the previous questions asked dating Feb. 02, 2013

1. So the overall idea is that dissociation decreases molar mass and association does the opposite when a solute dissolves in a solvent. (How do you identify if either reaction occurs? Just wondering.)

2.So in this case, that a small amount of your unknown failed to dissolve in the t-butanol, it would effect the molar mass, just depending on the mass of both substances?

Thanks for your time

1. Dissociation decreases the IONIC mass (the molecule is gone) and association increases the molar mass. Experience is probably the best indicator of which is going on.

2. I've forgotten the t-butanol part of the question.

Hello! I'm here to answer your follow-up questions. Let's go through each question one by one.

1. To identify whether dissociation or association occurs when a solute dissolves in a solvent, you can consider factors such as the nature of the solute and the solvent, the temperature, and any other relevant conditions.

Dissociation typically occurs when a solute breaks apart into its constituent ions or molecules in the solvent. This is common for ionic compounds, such as salts, which can readily dissociate into their respective ions.

Association, on the other hand, occurs when solvent molecules come together to surround the solute particles. This generally happens when the solute is a nonpolar molecule that can form weak interactions, like hydrogen bonding, with the solvent molecules.

In both cases, the extent of dissociation or association can be influenced by factors such as temperature, pressure, and concentration.

2. If a small amount of your unknown substance fails to dissolve in t-butanol, it may indeed affect the measured molar mass. When you calculate the molar mass of a solute dissolved in a solvent, you typically assume that complete dissolution has occurred. If only a small fraction of the solute dissolves, it may introduce an error in the calculated molar mass.

To minimize this error, it is crucial to ensure that the solute is fully dissolved in the solvent before performing any measurements or calculations. If the solute is not completely soluble, it would be advisable to find an alternative solvent that can dissolve the entire sample.

I hope this helps! Let me know if you have any further questions.