Identify the intermolecular attractive force(s) that must be overcome to vaporize CH3Cl(l).
Wouldn't that be dipole-dipole?
To vaporize CH3Cl(l) (methyl chloride), the intermolecular forces that need to be overcome are:
1. London dispersion forces: These forces exist between all molecules and are caused by temporary shifts in electron density, leading to temporary dipoles. In the case of CH3Cl, the dispersion forces arise from the interaction between the temporary dipoles of neighboring CH3Cl molecules.
2. Dipole-dipole forces: CH3Cl is a polar molecule since chlorine (Cl) is more electronegative than carbon (C) and attracts electron density more strongly. This creates a permanent dipole moment in the molecule. Dipole-dipole forces occur between the positively charged hydrogen atom of one CH3Cl molecule and the negatively charged chlorine atom of a neighboring CH3Cl molecule.
These intermolecular forces must be overcome by adding energy in the form of heat to break the attractions between the CH3Cl molecules and allow them to become a gas (vaporize).
To identify the intermolecular attractive forces present in a substance, you need to consider the molecular structure and properties of the substance. In the case of CH3Cl (methanol), it is important to note that CH3Cl is a polar molecule. Hence, the intermolecular forces at play here are primarily dipole-dipole interactions and London dispersion forces.
Dipole-dipole interactions occur between polar molecules due to the attraction between the positive end of one molecule and the negative end of another molecule. In the case of CH3Cl, the carbon-chlorine bond is polar, with chlorine being more electronegative than carbon. This results in a partial positive charge on the carbon atom (δ+) and a partial negative charge on the chlorine atom (δ-). The δ+ of one molecule will be attracted to the δ- of another molecule, creating dipole-dipole interactions.
In addition to dipole-dipole interactions, CH3Cl also experiences London dispersion forces. Even though CH3Cl is a polar molecule, it also possesses temporary fluctuations in electron density distribution, resulting in instantaneous temporary dipoles. These temporary dipoles can induce temporary dipoles in neighboring molecules, leading to London dispersion forces.
When vaporizing CH3Cl, these intermolecular forces need to be overcome. The energy required to break these forces and convert the liquid to a vapor is called the heat of vaporization.
In summary, the intermolecular attractive forces that need to be overcome to vaporize CH3Cl(l) are primarily dipole-dipole interactions and London dispersion forces.