Boiling/Melting Point

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Natalie Phan 3G
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Boiling/Melting Point

Postby Natalie Phan 3G » Wed Nov 18, 2020 10:09 pm

When determining which molecule has a higher boiling/melting point, do we look at the inter or intramolecular forces?

Margaret Xu 3C
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Re: Boiling/Melting Point

Postby Margaret Xu 3C » Wed Nov 18, 2020 10:16 pm

Hi Natalie! We look at intermolecular forces because the bonds between the molecules are being broken, not the bonds holding each molecule together. Compounds with stronger IMFs will have higher melting/boiling points.

Nathan Lao 2I
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Re: Boiling/Melting Point

Postby Nathan Lao 2I » Wed Nov 18, 2020 10:30 pm

We would look at intermolecular forces since those are the attractions between the molecules. For example, if the IMFs are stronger in one compound, they would "stick together" more than the other compound and have a higher boiling point(more energy would be needed to break those intermolecular attractions).

Anirudh Mahadev 1G
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Re: Boiling/Melting Point

Postby Anirudh Mahadev 1G » Thu Nov 19, 2020 3:49 pm

We would look at intermolecular forces because those are the forces that are overcome to initiate a phase change. For example, when H2O (liquid) is evaporated into H2O(gas) the Hydrogen bonds in the liquid have been overcome to separate the molecules. The O-H bonds in each H2O molecule have not been broken.

Ariel Guan 1H
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Re: Boiling/Melting Point

Postby Ariel Guan 1H » Thu Nov 19, 2020 5:04 pm

You look at intermolecular forces

AmyHo2K
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Re: Boiling/Melting Point

Postby AmyHo2K » Thu Nov 19, 2020 5:29 pm

We look at intermolecular forces because we want to see the interactions between the molecules.

MCalcagnie_ 1D
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Re: Boiling/Melting Point

Postby MCalcagnie_ 1D » Thu Nov 19, 2020 7:04 pm

You are going to want to focus on intermolecular forces because those are between molecules, which would be separating as a result of boiling or melting. Intramolecular forces are within the individual molecules themselves, which are not being separated by the melting or boiling.

Andre Fabian 1F
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Re: Boiling/Melting Point

Postby Andre Fabian 1F » Thu Nov 19, 2020 9:59 pm

In determining melting and boiling point, we would look at intermolecular forces, given that these are formed between molecules. In order to change the state of a species, we must first excite or slow down the individual molecules in order for them to separate (i.e. increasing the temperature to excite water molecules to turn them from a liquid to a gas).


Hope this helps!

Uyenvy Nguyen 1D
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Re: Boiling/Melting Point

Postby Uyenvy Nguyen 1D » Thu Nov 19, 2020 10:13 pm

We would look at the intermolecular forces!
Intermolecular: between molecules
Intramolecular: within molecules

Lorraine Medina 3E
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Re: Boiling/Melting Point

Postby Lorraine Medina 3E » Fri Nov 20, 2020 1:06 am

We would look at intermolecular forces in order to understand what is occuring between molecules. Hope this helps!

Navdha Sharma 3J
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Re: Boiling/Melting Point

Postby Navdha Sharma 3J » Fri Nov 20, 2020 7:47 am

You would look at the intermolecular forces. As the intramolecular forces don't contribute towards the melting/boiling points.

Binyu You
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Re: Boiling/Melting Point

Postby Binyu You » Fri Nov 20, 2020 8:41 am

I would say to look more into intermolecular bonds. If comparing different elements' boiling or melting point, the higher it is, the stronger the bond is. Several factors to consider to rank boiling/melting point include if hydrogen bond exist as well as the size of an element. The more protons it has, the larger its nucleus, the higher the boiling point.

Melanie Lin 3E
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Re: Boiling/Melting Point

Postby Melanie Lin 3E » Sun Nov 22, 2020 9:06 pm

Hi Natalie! You generally look into intermolecular forces to see if the molecule is nonpolar or polar. Once you figure that out, you determine the type of intramolecular force that the molecules have with each other. So the BP and MP are mostly determined by the strength of the intramolecular forces.

105618850
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Re: Boiling/Melting Point

Postby 105618850 » Sun Nov 22, 2020 10:11 pm

Hey! I believe we examine intermolecular forces when determining the boiling point because we are not separating the atoms that compose the molecule, yet the forces that hold identical molecules together.

LovepreetSran_3H
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Re: Boiling/Melting Point

Postby LovepreetSran_3H » Sun Nov 22, 2020 10:14 pm

When determining the boiling point and melting points we look at the intermolecular forces.

Hasan Mirza 3F
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Re: Boiling/Melting Point

Postby Hasan Mirza 3F » Sun Nov 22, 2020 10:21 pm

Intermolecular forces such as London forces and hydrogen bonding will require more energy to break bonds and allow boiling to occur.

Aydin Karatas 1F
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Re: Boiling/Melting Point

Postby Aydin Karatas 1F » Sun Nov 22, 2020 10:25 pm

Intermolecular forces because it is the force between or "inter" molecules are responsible for holding materials together. Melting and boiling would cause these forces to weaken. Thus, we go from solid --> liquid --> gas.

MichaelMendozaD1F
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Re: Boiling/Melting Point

Postby MichaelMendozaD1F » Wed Nov 25, 2020 12:31 am

So do we always take the placement on the periodic table first, or simply look to electronegativity, if given?

Muskaan Abdul-Sattar
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Re: Boiling/Melting Point

Postby Muskaan Abdul-Sattar » Sun Nov 29, 2020 9:51 pm

If a compound has higher intermolecular forces then its boiling point will be higher!

Aria Movassaghi 1A
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Re: Boiling/Melting Point

Postby Aria Movassaghi 1A » Sun Nov 29, 2020 10:33 pm

You would look at intermolecular interactions because those are the interactions between molecules

Hasan Mirza 3F
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Re: Boiling/Melting Point

Postby Hasan Mirza 3F » Sun Nov 29, 2020 10:36 pm

Intermolecular forces like london dispersion and hydrogen bonding play a big role in boiling and melting points.


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