Intermolecular forces (Exam 4)

How do strong IMFs affect boiling point, melting point, and energy of phase transition?

Higher boiling point, higher melting point, and increased energy for phase transitions

Types of IMFs?

Ion-ion, dipole-dipole, ion-dipole, ion-ID, dipole-ID, H bond, London dispersion

Rank IMFs from strongest to weakest

(Strongest) Ion-dipole, Hbond, Dipole-dipole, ion-ID, dipole-ID, london dispersion forces

Ion - dipole IMF

when and ion and a dipole interact (often when putting an ion in a polar substance)

What is an induced dipole?

When a nearby atom/molecule with a charge distorts the electron cloud of a non-polar atom, and creates a temporary dipole

Ion - ID IMF

an ion interacts with the electron cloud of a neutral/non-polar atom and creates a temporary charge

Dipole - Dipole IMF

molecules with permanent dipoles are attracted to each other

Hydrogen bond IMFs

A dipole-dipole interaction with a donor and an acceptor. A partially positive H interacts with the partial negative lone pair from the donor atom

What would happen without hydrogen bonding?

The boiling point of everything would decrease tremendously

What are donors in hydrogen bonding?

H is bound to N, O, F

What is the acceptor in hydrogen bonding?

A lone pair in N, O, F

Why is hydrogen bonding so strong in H2O?

Are induced dipoles weak or strong?

weak(but can be strong with many together)

How to determine which molecule should have the highest boiling point?

Look for H-bonding(acceptors and donors), then look dipoles, then large molecules

Are ion-dipoles strong or weak?

Very strong

What interaction makes it possible for ionic substances to dissolve in polar substances?

Ion-dipole interactions

Is an ion-dipole interact with 2+ or 1+ charge stronger?

2+

Polarizability

how easy it is to induce a dipole(by distorting the electron cloud)

What is polarizability dependent on?

The number of electrons (inherently also size of atom)

Are cations more or less polarizable than anions?

Less (because they have fewer electrons)

How do you determine which molecule is most soluble in water?

The most polar molecule is the most soluble, and smallest(larger molecules are less soluble)

How do you determine the most polar molecule?

The molecule with polar bonds, or the largest fraction of polar bonds