AP Chemistry Formulas and Common Ideas

How much does 1 mole equal to particles?

6.022×10²³ particles

Formula for Moles

Grams/MM

Formula for changing gas laws

PV=NRT R=0.08206

Molarity Formula

M=mol/Liters

STP always occupies how many Liters?

22.4 Liters

How do you find Empirical Formula?

If given percent of element convert to grams and divide by MM. The smallest number of each is to be divided by all. That will give you the Empirical Formula.

How do you find the Molecular formula?

Once you’ve found the empirical formula, multiply by the molar mass of the compound divided by the molar mass of the empirical formula.

Coulombs law

describes the force between two charged objects, indicating that the force is proportional to the product of the charges and inversely proportional to the square of the distance between them.

Photoelectron spectrum (PES)

Atomic Radius trend

Decreases across a period and increases down a group due to increasing nuclear charge and electron shielding.

Ionization Energy trend

Increases across a period and decreases down a group. This trend occurs because higher nuclear charge attracts electrons more strongly, while additional electron shells increase shielding and distance from the nucleus.

Electronegativity trend

Increases across a period and decreases down a group. F has the highest electronegativity

Ionic bonds

Strong and hold ions tightly in a lattice. High melting and boiling points. Metal and Non-metal.

Lattice energy

Bond energy required to break ions out

Difference between Interstitial alloy and substitutional alloy

Interstitial alloy are metal atoms with two vastly different radii combine, while substitutional alloys have similar radii and replace each other in the lattice.

Metallic Bonding

“sea of electrons” Good conductors of electricity and heat.

Molecular covalent bonding

A type of chemical bonding where atoms share pairs of electrons to achieve stability. These compounds generally have low melting points and do not conduct electricity. (Non-metals)

Internuclear distance

Elements with more bonds will be closer to the left and down more (double or triple bonds), while single bonds will be further to the right and up to the axis more.

Network Covalent

Diamonds, high boiling/melting point (SiO2)

Formal Charge

(# of valence electrons in free, neutral atom)-(# of valence electrons allocated {# of lone pair electrons+1/2# of shared electrons} to bonded atom) -see what group the element is and subtract by number of valence electrons. when there is more zeros in the balanced Lewis dot that is the better Lewis dot

Linear

180 degree bond angle; straight shape. Hybridization: sp

Trigonal Planar

120 degree bond angles; flat shape. Hybridization: sp2

Bent or Angular

Bond angles less than 120 degrees; V-shaped molecule. Hybridization: sp2 or sp3.

Tetrahedral

109.5 degree bond angles; three-dimensional shape. Hybridization: sp3.

Trigonal Pyramid

107 degree bond angles; pyramid shape with one lone pair of electrons. Hybridization: sp3.

Bent or Angular

2 lone pairs of electrons create a V-shape, affecting bond angles.

Trigonal Bipyramidal

90 degrees, sp3d

Seesaw

molecular shape with five regions of electron density, one equatorial lone pair, resulting in 90 and 120 degree bond angles.

T-shape

molecular shape with three bonding pairs and two lone pairs of electrons, creating 90-degree bond angles.

IMFs

LDF, Dipole-Dipole, Hydrogen Bonding

Dissolving

“LIKE DISSOLVES LIKE”

Distillation

A separation technique that takes advantage of differences in boiling points of substances in a mixture.

The Kinetic Energy of a single gas molecule

KE=1/2mv²

Maxwell-Boltzmann Diagrams

Graphical representations of molecular speed distributions in gases, illustrating the relationship between temperature and the kinetic energy of gas molecules.

Combined Gas Law

P1V1/T1=P2V2/T2

Dalton’s law

Ptotal=Pa+Pb+Pc…

Partial Pressure

Pa=Ptotal(Xa) Xa=moles of gas A/total moles of gas

Molar Mass equation

MM=drt/p

Energy and Electromagnetic radiation

deltaE=hv=h times c/wavelength Planacks constant=h=6.626×10^-34

Beers Law

A=Ebc E=molar absortivity b=path length in cm, c=concentration in mol/L

What two characteristics must an effective collision have?

(1) Sufficient kinetic energy (2) Correct orientation

Strong Acids

HCl, HBr, HI, HCIO3, HCIO4, HNO3, H2SO4

Which of the IMFs is generally the weakest?

LDF

What type of alloy is made when the radii of the atoms are similar in size?

Substitutional

How will the percent ionization of a weak acid change if water is added to it?

Increase

According to Coulomb’s Law, which TWo properties of an electron determine the strength of attraction to the nucleus?

Effective nuclear charge and Distance between electrons and nucleus

If Q increase, the voltage (Ecell) of the battery ? relative to E?

Decreases

Distillation separates mixtures based on

Boiling points

If a reaction increases the number of moles of gas, the sign for delta S would be

Positive

Which of the following does NOT speed up a chemical reaction?

Increase the concentration of a product

Temperature is the (blank) of particles?

Average kinetic energy

Percent ionization

The degree to which an acid or a base dissociates in solution, expressed as a percentage of the total concentration.

Adding conjugate base to a weak acid solution (blank) the percent ionization of the acid?

Decreases

What is the approximate bond angle of H2O?

109.5 degrees

Which TWO properties would cause high lattice energy in an ionic solid?

Small ionic radii and high ion charges

If a reaction is exothermic, the average bonds in the products formed are (blank) than the average bonds in the reactants?

Stronger

If a reaction is endothermic, the average bonds formed in the products are (blank) than the average bonds broken in the reactants?

Weaker

MaVa=MbVb at which point in a monoprotic acid/base titration?

The equivalence point

When forming an ionic bond…

Electrons transfer from a metal to a nonmetal

T or F: As acid concentration increases, percent ionization also increases

False

At constant volume, decreasing the temperature of a gas will cause the pressure to…

Decrease

An endothermic reaction feels ? and has a ? delta H

Cold;positive

If delta G is negative, then K is

Greater than 1

T or F: Spontaneous reactions are always fast

False

What are TWO components of a buffer?

Conjugate (base or acid) and Weak (acid or base)