AP Chemistry

Filtration

a physical separation technique used to isolate an insoluble solid (precipitate) from a liquid or solution.

Distillation

a physical separation technique that purifies liquid mixtures based on boiling point

Paper chromatography

separates chemical species in a solution based on differences in their intermolecular interactions (polarities) with a mobile phase and a stationary phase

Column Chromatography

a separation and purification technique that splits a mixture of components based on their differing affinities (intermolecular forces) for a stationary phase and a mobile phase, more appropriate for separating the components in a mixture on a larger scale.

Anything that DECREASES the amount of light passing through during a spectrophotometer experiment cause an _______ in absorbance

increase

The absorption of photons of infrared radiation is associated with

transitions in molecular vibrational levels

Absorption of photons in the visible range will cause

transition of electrons between electron energy levels.

By Kinetic Molecular Theory, gas particles are always moving at ____ speeds

a variety of different

By coloumb’s law, ionic compounds with bigger charges have

higher melting points

By coloumb’s law, ionic compounds with the same charge but have smaller ions have

higher melting points

Isotopes differ in

neutrons

Generally, smaller atoms will have ___ and therefore ____ bond lengths

shorter, stronger

by VSEPR Theory, 2 groups means its shape is

Linear

by VSEPR Theory, 3 groups, NO LONE PAIRS means its shape is

Trigonal planar

by VSEPR Theory, 3 groups with ONE LONE PAIR means its shape is

bent

by VSEPR Theory, 4 groups with NO LONE PAIRS means its shape is

tetrahedral

by VSEPR Theory, 4 groups with ONE LONE PAIR means its shape is

Trigonal Bipyrimidal

by VSEPR Theory, 4 groups with TWO LONE PAIRS means its shape is

Bent

Stronger intermolecular forces results in

Higher melting and boiling point, lower vapor pressure, higher viscosity

Properties of ionic solids

brittle, conduct electricity in molten state only, held together by ionic bonds

Properties of covalent networks

Nonmetals and metalloids, rigid and hard, high melting points, held together by covalent bonds

Properties of molecular solids

Made of individual molecules, low melting point, held together by IMFs

Metallic solids

conduct electricity and heat, held together by metallic bonds

When will gasses have lower pressure than expected

at low temperatures or with gasses with stronger IMFs

When will gasses have higher pressure than expected

Extremely small volumes

At high pressures, what will volume do?

volume will be bigger than expected

How do you experimentally determine the order of a reaction

Change reaction concentration and observe how rate responds

Infrared radiation is used to study

bonds within molecules

Solid to liquid is called

melting/fusion

liquid to gas is called

vaporization

solid to gas is called

sublimation

gas to solid is called

deposition

When manipulating Keq, when you multiply a reaction by a coefficient you must

raise it to the power of that coefficient

When manipulating Keq, when you add two reactions you must

multiply their Keqs

Stronger acids(or bases) have ____ conjugate bases(or acids).

weaker

Stronger species (acids/bases) are

less stable and more reactive

Strong acids

H2SO4, HI, HBr, HNO3, HCL, HClO4

What are the strong bases

Group 1 and 2 hydroxides (LiOH, NaOH, etc)

What is the heat of vaporization

the amount of energy needed to break all intermolecular forces

Vapor pressure

the pressure exerted by the gas above a liquid at equilibrium, indicates how easily a liquid's molecules escape into the gas phase

Volatility

a measure of how easily a substance evaporates at a specific temperature

Properties when a substance has stronger IMFs

higher boiling point, heat of vaporization, surface tension, and viscosity, lower vapor pressure and volatility

A molecule with a SHORTER bond length will result in what changes to the graph

shift to the left and lower peak (shorter=greater energy)

Gasses stray from ideal gas law due to

low temperatures, stronger IMFs, large particles, small containers, high pressures

In paper chromatography, the stationary phase is the _____ and the mobile phase is the ____

paper (what the solution separates into), solvent (the solvent that passes through the stationary phase)

The pH of the conjugate base of a strong acid is

neutral

The PH of the conjugate acid of a weak base is

acidic

The more electronegative an atom is (acids/base) + trend on periodic table

the more acidic; across a row= more acidic

The bigger an atom ______, + periodic trend

the weaker the acid, down a column= weaker acids

Acids with resonance are ____ than acids without resonance

stronger

Strong acid + strong base will result in a pH ____

neutral

Strong acid + weak base will result in a pH ____

less than 7 (acidic)

Weak acid and strong base will result in a pH

greater than 7 (basic)

A buffer is more effective when

the concentration of the conjugate pair are higher

The autoionization of water is an ______ process, so warming up water ______ the pH

endothermic, decreases