AP Chemistry Thou Shalt Not Forget

Compounds

They can be separated into elements by chemical changes

Mixtures

can be separated by physical changes and based on differences in particle size, the larger one is trapped on the filter paper

Distillation

separates mixtures based on differences in boiling points

Chromatography

separates mixtures based on differences in polarity

Paper chromatography

the component that is most similar in polarity to the mobile phase moves up the farthest.

When is mass converted?

during chemical and physical change

Reading the volume of a liquid in a container

you can estimate It by looking in between the gradual markings and this can give you one more sig fig

Least precise measurement to more precise measurement

beaker, graduated cylinder, volumetric flasks, burette. (volumetric flash has one line on it to measure specific volume)

What does density equal?

mass/volume

What doesn’t change for a pure compound?

the % composition by mass

When an electron is in a higher energy level

it is farther away from the nucleus and has less Coulumbic attraction

Moving across a row on the periodic table

The Zeef(effective nuclear charge) increases and the valence electrons are more attracted to the nucleus

When reading a PES graph

the higher the peak, the more electrons there are in that sublevel and a larger binding energy

When writing the electron configuration for a cation

remove the valence electrons first

Isotopes of an element

have the same number of protons but different numbers of neutrons

Mass spectroscopy

graphs measure atomic masses of isotops

Elements in the same group

have similar chemical and physical properties

Metals are on the

left side of the zig zag line

Non metals are on the

right side of this line of the periodic table

Cations(+) are smaller than their atoms

because you are removing valence electrons that are farther from the nucleus

anions(-) are larger than their atoms

since adding extra electrons increases electron-electron repulsion

Covalent bonds form between

two nonmetals sharing electrons

Ionic bonds are formed when

a metal transfers electrons to a nonmetal and the opposite charges attract

The greater the electronegativity difference

the more polar the bond becomes

Combustion reactions make

CO2 and H2O

Diatomic elements

H O N Cl Br I F

Empirical formula rhyme

% to mass, mass to mole, divide by small, time until whole

% yield

experimental/theoretical

% error

(experimental - theoretical)/theoretical

The amount of production for a reaction is determined by

the limiting reactants

Why are gas minutes homogeneous?

because of the constant random motion of particles

Why are Gases compressible?

because of the large spaces between the particles

What is gas pressure caused by?

by the collisions of particles with the walls of the container. More collisions will mean more pressure

How are T and V related?

directly related (heat a balloon it will expand)

How are T and P related

directly related, heat a container and the pressure will increase

Gas constant R

0.08206

One of an idea gas

22.4 L

How is gas pressure and number of moles related

directly related (double the moles and the pressure will double)

The more molar mass a gas will

move slower at a given temperature

Temperature =

Average Kinetic Energy

Gas by water displacement

Ptotal = Pdry gas + Pwater vapor

Real gases behave like

most ideal gas at high temperature and low pressure

The more polar and larger a gas is

it will deviate from ideal behavior

Small nonpolar gases are

the most ideal