All Questions
8 questions
3
votes
1
answer
619
views
Why does N,N-dimethylethanamide have a higher boiling point than butanoic acid?
According to Wikipedia, N,N-dimethylethanamide has a boiling point of $\pu{165.1 °C},$ while butanoic acid has a boiling point of $\pu{163.75 °C}.$
From what I learned, butanoic acid should have a ...
- 281
5
votes
1
answer
2k
views
For two compounds that are symmetrical, why does the more compact one have a higher melting point?
In this post, I refer to two molecules B (Di-tert-butyl ether) and C (Dibutyl ether).
Wikipedia: Di-tert-butyl ether (B)
b.p. 107.2 C
m.p. - 61 C
...
- 155
1
vote
2
answers
7k
views
Why does branching decrease density and melting point?
The general explanation given is that the chains are further apart, so the intermolecular forces are less, and as they are further apart, they occupy more volume, and the density is lesser. But the ...
- 495
0
votes
1
answer
9k
views
Which of these functional groups is soluble in aqueous HCl and/or NaOH?
http://pastpapers.papacambridge.com/view.php?id=Cambridge%20International%20Examinations%20%28CIE%29/AS%20and%20A%20Level/Chemistry%20%289701%29/2015%20Jun/9701_s15_qp_42.pdf
I need some help to ...
- 495
2
votes
2
answers
458
views
Why is polymer B more dense than polymer A?
The official solution is that A has branched / side chains, weak Van der Waals forces between the polymer chains, less compact packing than B, and large inter-chain distances.
B has no branched chains,...
- 495
7
votes
1
answer
229
views
Computational Chemistry: calculation of sterical effects
Is there a way to calculate sterical forces between atoms/groups of atoms (preferably with free and open source tools)? I have heard that this is possible within the framework of NBO. I am using ORCA, ...
- 2,804
9
votes
1
answer
415
views
Why do dianions (such as malonate) bind cations more strongly than anions?
Why does a dianion (such as malonate) bind cations more strongly than its equivalent anion (acetate)?
Is it simply because of the proximal availability of another $\ce{O-}$ group that can bind to ...
- 339
2
votes
0
answers
1k
views
Structure of fluoroalkylsilane
I want to use FAS (fluoroalkylsilane) in my molecular dynamics study. How can I find it's real structure? So that I can find proper forcefield for simulating the molecule. It would be very nice if you ...
- 141