Organic Questions

[umc27]

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Hello everyone. I was wondering if there were allot (or any) questions on the real DAT about the boiling points or melting points of various funcitonal groups? Were there questions about solubilities, etc?

 

[Aurora]

Hello everyone. I was wondering if there were allot (or any) questions on the real DAT about the boiling points or melting points of various funcitonal groups? Were there questions about solubilities, etc?

I don't remember having any questions about boiling pts or solubilities on my DAT...but I would still know it if I were you. The principles for boiling points are pretty simple. The stronger the hydrogen bonds a functional group is capable of the higher the boiling point...like alcohols have higher boiling points than alkanes of the same MW. Then also boiling point increases with MW.

Then for solubility just remember like dissolves like---so polar molecules will dissolve best in polar solvents. Alcohol and carboxylic acids which are polar and form hydrogen bonds dissolve very well in water.

I don't really understand why you are worried about these two things. Anyway, hope this helps.

Aurora

 

[Awuah29]

I don't remember having any questions about boiling pts or solubilities on my DAT...but I would still know it if I were you. The principles for boiling points are pretty simple. The stronger the hydrogen bonds a functional group is capable of the higher the boiling point...like alcohols have higher boiling points than alkanes of the same MW. Then also boiling point increases with MW.

Then for solubility just remember like dissolves like---so polar molecules will dissolve best in polar solvents. Alcohol and carboxylic acids which are polar and form hydrogen bonds dissolve very well in water.

I don't really understand why you are worried about these two things. Anyway, hope this helps.

Aurora

Hey Aurora,
doesn't hurt to go over laboratory techniques . What do you think? I don' t know if DAT cover this topic

 

[umc27]

You're correct... im probably worrying over nothing... thanks for the tips though!

 

[Calculus1]

Hey Aurora,
doesn't hurt to go over laboratory techniques . What do you think? I don' t know if DAT cover this topic

Kaplan told me when I was teaching there that lab techniques were fair game, but no one had actually had any questions over it yet(they told us not to spend much time on it).

 

[edkNARF]

I had questions like, "Which of these would have the highest boiling points?" There were a bunch of aliphatic molecules and one alcohol. You needed to know that the OH group will let the alcohol H-bond, which would raise boiling point. I also had a similar melting point question. The questions were really "which one of these answers is not like the other..." You really need to be able to look at the answer choices and see which one was different.

 

[Aurora]

You're correct... im probably worrying over nothing... thanks for the tips though!

Hi,

I think you should definitely know these subjects. I think they are simple enough that you shouldn't really be worried about it. It's important to know which functional groups can form hydrogen bonds anyway...they could ask about hydrogen bonding and not even relate it to bp or mp.

Good luck 🙂

Aurora

 

[Aurora]

Hey Aurora,
doesn't hurt to go over laboratory techniques . What do you think? I don' t know if DAT cover this topic

I don't remember any questions about lab techniques on the DAT. But again I think these things are really simple...should take 1-2 hours to study. I think it's worth studying even if there is any chance of a question being in the DAT.

Aurora

 

[sxr71]

Hi,

I think you should definitely know these subjects. I think they are simple enough that you shouldn't really be worried about it. It's important to know which functional groups can form hydrogen bonds anyway...they could ask about hydrogen bonding and not even relate it to bp or mp.

Good luck 🙂

Aurora

Yep, if it has a lone pair on it then generally it can do hydrogen bonding. -OH, -SH, -NH are the ones that come to mind off the top of my head.

Two polar groups raises BP more than one polar group, branching has an effect on BP but I don't think the DAT really requires you to know what effect branching has on BP.