Arrange the compounds in order of increasing boiling point.
A) CH4
B)CH3CH3
C) CH3CH2Cl
D) CH3CH2OH
**I know High Intermolecular force = High boiling point!**
My question is if A, B & C are dipole-dipole, and D is hydrogen bonding.. how can i determine from A, B & C which is the highest of those three. Is it the molar mass of each compound?..
Im just stuck on a practice exam and was wondering if they all are the same what is the second thing that can determine the high boiling point.
Thanks
molar mass. The higher the molar mass the higher the boiling point.
CH4 is not polar. Neither is CH3CH3.
Yes. D is highest. CH4 is lowest. Then in order, CH3CH3 is next and chloroethane is next.
If all compounds A, B, and C have similar intermolecular forces (dipole-dipole interactions), the next factor to consider in determining their boiling points would be their molar masses.
Generally, as the molar mass of a compound increases, the boiling point also tends to increase. This is because larger molecules have more electrons and more surface area, leading to stronger intermolecular forces.
So, if all compounds have similar intermolecular forces, you can arrange them in order of increasing boiling point based on their molar masses:
A) CH4 - molar mass = 16 g/mol
B) CH3CH3 - molar mass = 30 g/mol
C) CH3CH2Cl - molar mass = 64.5 g/mol
Therefore, the order of increasing boiling points would be:
A) CH4 < B) CH3CH3 < C) CH3CH2Cl
Please note that these are general trends, and there may be exceptions depending on the specific molecules and their structural characteristics.
To determine the order of increasing boiling point among compounds A, B, and C (all of which are dipole-dipole) based on factors other than molecular mass, you can consider the strength of the dipole-dipole interactions present in each compound.
The strength of dipole-dipole interactions is determined by the polarity of the molecules. The polar molecule has a positive and negative end, leading to stronger attractions between the molecules and higher boiling points.
Among compounds A, B, and C, you can compare the dipole moments to determine their relative polarity. Generally, the presence of more electronegative atoms or groups in a molecule increases its polarity and, consequently, strengthens the dipole-dipole interactions.
In this case, among A, B, and C, CH3CH2Cl (compound C) is the most polar due to the chlorine atom. Chlorine is more electronegative than carbon, making the C-Cl bond more polar. This increased polarity results in stronger dipole-dipole interactions compared to compounds A (CH4) and B (CH3CH3).
Therefore, the order of increasing boiling point for compounds A, B, and C would be:
A (CH4) < B (CH3CH3) < C (CH3CH2Cl).
Keep in mind that this ordering considers only the dipole-dipole interactions present in the compounds. If compound D (CH3CH2OH) is included as well, its hydrogen bonding (a stronger type of dipole-dipole interaction) would make it have the highest boiling point among all the mentioned compounds.
In summary, the factors to consider for determining the order of boiling point are:
1. Molecular mass (in cases where compounds have similar intermolecular forces).
2. Intermolecular forces (in this case, dipole-dipole interactions).
3. The presence of stronger intermolecular forces like hydrogen bonding.