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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.
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).
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.
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.
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!
Hope this helps!
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.
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.
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.
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