AP Chemistry Unit 3

London Dispersion Forces

weakest intermolecular force, strength dependent on Electron Cloud Size. More Electrons = Stronger Force

Dipole-Dipole Forces

Intermolecular forces only found in polar molecules, between the positive and negative ends of the molecules. Stronger than London dispersion forces.

Ion-Dipole Forces

Forces of attraction between ions and polar molecules. Stronger than dipole-dipole forces 

Hydrogen Bonding 

Intermolecular Interaction that exists when hydrogen atoms are covalently bonded with highly electronegative atoms (N, O & F) are attracted to the negative end of a dipole formed by the electronegative atom (N, O & F) in a different molecule. Stronger Intermolecular Force. 

polarizability

the ease with which the electron cloud in an atom or molecule can be distorted

Hydrogen Bond Donor

Substance contains a hydrogen atom that is covalently bonded to a highly electronegative atom (N, O & F)Hydro

Hydrogen Bond Acceptor 

The substance contains a highly electronegative atom (N, O & F) with a lone pair of electrons on it. This atom (N, O & F)  has a partial negative charge on it because its part of a polar bond (Dipole)

Vapor Pressure

pressure exerted by a gas in equilibrium with its liquid phase at a given temperature. Low Pressure=High boiling point, high pressure= low boiling point

Boiling Point

temperature at which the vapor pressure of the liquid is equal to the external pressure surrounding the liquid.

Normal Conditions

pressure= 1atm or 760 torr

Ionic Solids

Positive and Negative Ions, electrostatic attractions between oppositely charged ions, no conduction in solid state, however some in liquid state. High Melting point, Hard/brittle. ex: LiBr, MgO and CuSO4

Covalent Network Solid 

atoms, covalent bonds between atoms in a large extended network, never conducts, relatively high melting point, hard/rigid. MUST KNOW: Diamond (C), Graphite(C), Silicon(Si), Quartz(SiO2), Silicon Carbide(SC), Boron Nitride (BN)

Molecular Solid

Molecules, Intermolecular attractions between molecules, never conducts, low melting point, soft. ex: I2, H2O, C6H12O6

Metallic Solids

Positive metal cations and valance electrons, attractions between positive metal cations and a sea of delocalized electrons. Conducts, range of melting points, malleable and ductile. Ex: Na, Mg & Al

PV=nRT (Ideal Gas Law)

equation that represents the properties of ideal gases

Properties of an “Ideal Gas” 

Gas Particles are in constant random, rapid motion. Gases expand to fill their container completely. Two or more gases will form homogeneous mixture when they are combined. Gases are highly compressible. No attractive force between gas particles 

Kinetic Molecular theory (KMT)

relates the properties of gases to the motion of gases. Describes the distribution of kinetic energy of particles at a given temperature