I'm getting crushed by Chem! Help!?

Question

I have no idea why this is?

A molecule of formaldehyde has the same shape as a methane molecule but the boiling points are a lot different. explain the difference between the boiling points, include lewis structures.

I have no idea why they are different in boiling point. One's a gas and ones a solid, but how would i draw them to show the difference?

Answer 1

Clue: formaldehyde is more polar than methane.

Answer 2

i have no idea what those compounds are so i can't help you with lewis dot structures... but things boil faster because they are non-polar, their molecules don't stick together so they lift off more easily.

In a COVALENT molecule like water, valence electrons are being shared>that's why the hydrogen and oxygen are bonded. But the electrons are pulled more towards oxygen because it has a higher electron affinity(lots of protons in core), making the oxygen side slightly negative and the hydrogen side slightly positive. Hence the term polar. In water, the molecules will arrange themselves so that the negative pole of one molecule will "attach" to the positive pole of another(hydrogen bond). Water is very polar and has a high boiling point.

The way the elements are bonded makes a difference too.
Ex: O-C-O (CO2) there is a pull in both directions toward oxygen, b/c of that the intermolecular forces cancel out making CO2 a non-polar molecule.

Answer 3

In terms of intermolecular interactions, the boiling point represents the point at which the liquid molecules possess enough heat energy to overcome the various intermolecular attractions binding the molecules into the liquid (eg. dipole-dipole attraction, instantaneous-dipole induced-dipole attractions, and hydrogen bonds). Therefore the boiling point is also an indicator of the strength of these attractive forces.

The three dimensional shape or configuration of a molecule is an important characteristic. This shape is dependent on the preferred spatial orientation of covalent bonds to atoms having two or more bonding partners.

One way in which the shapes of molecules manifest themselves experimentally is through molecular dipole moments. A molecule which has one or more polar covalent bonds may have a dipole moment as a result of the accumulated bond dipoles.

Answer 4

formaldehyde is polar
it is and aldehyde's ie carbon has a bond with hydrogen and oxygen

-
- C -h
\
o


so there is hydroen bonding b/w molecules which is the Strong force of attracton
and there is oxygen too which has lone pairs so there is a fromatin of dipole dipolr attraction