Honor Bio 5.3 Flashcards
What are London dispersion forces?
London dispersion forces are weak intermolecular attractions caused by the temporary dipoles formed when electrons move around in atoms and molecules.
What are dipole-dipole interactions?
Dipole-dipole interactions are attractive forces between polar molecules where the positive end of one molecule is attracted to the negative end of another.
What are hydrogen bonds?
Hydrogen bonds are strong dipole-dipole interactions that occur when a hydrogen atom covalently bonded to a highly electronegative atom (like N, O, or F) is attracted to another electronegative atom.
Rank the following intermolecular attractions from weakest to strongest: hydrogen bonds, London dispersion forces, dipole-dipole interactions.
London dispersion forces < dipole-dipole interactions < hydrogen bonds.
Rank the following intermolecular attractions from strongest to weakest: hydrogen bonds, London dispersion forces, dipole-dipole interactions.
Hydrogen bonds > dipole-dipole interactions > London dispersion forces.
How can you determine if a molecule is polar or nonpolar based on its structure?
A molecule is polar if it has polar bonds with an uneven distribution of charge and an asymmetric shape. It is nonpolar if it has nonpolar bonds or has a symmetrical shape causing charge cancellation.
Given a molecular structure, how would you determine what type of intermolecular attractions it can form?
Identify if the molecule has polar bonds and whether it can form hydrogen bonds (if H is bonded to N, O, or F) to classify the intermolecular attractions it can form.
How would you determine if a specific molecule is soluble in water based on its structure?
A molecule is likely soluble in water if it is polar and can form hydrogen bonds or dipole-dipole interactions with water, while nonpolar molecules generally do not dissolve well in water.
Consider the molecule CH3Cl (chloromethane). Is it polar or nonpolar, and what type of intermolecular attractions does it form?
CH3Cl is polar due to its C-Cl bond’s significant electronegativity difference, allowing it to form dipole-dipole interactions and some hydrogen bonding due to the hydrogen atoms.
