DAT Chemistry Study

mass percent

(mass of solute / mass of solution) x 100

mole fraction

mole of solute / total moles of solution

titration reactions equation

(acid) nMV = nMV (base)

Raoult’s Law

addition of solute lowers the vapor pressure of the solution

Psoln’ = (mole fraction of solvent) x Psolvent

diatomic molecules

H, O, N, F, Cl, Br, I

Allotropes

molecules with different formulas, whose atoms are all the same element

S6, S8, S12, all allotropes of sulfur

ammonium

NH4+

acetate

CH3COO-

cyanide

CN-

nitrate

NO3-

phosphate

PH4 (3-)

sulfate

SO4 (2-)

carbonate

CO3 (2-)

hydroxide

OH-

permanganate

MnO4-

naming Oxyacids HXO

1) hypo + -ous acid → Oxygen has 0-2 molecules

2) -ous acid → One more oxygen

3) -ic acid → One more oxygen

4) per + -ic acid → One more oxygen

Strong binary acids

HCl

HBr

HI

Strong Oxyacids

HClO3 → chloric acid

HClO4 → perchloric acid

HNO3 → nitric acid

HSO4 → sulfuric acid

mili

10³

micro

10^6

nano

10^9

1 m

3.28 ft

Percent Error

(actual-theoretical) / theoretical *100

Percent Yield

actual / theoretical *100

Lab coats repel

alpha particles

centrifuge

separate heterogeneous mixtures based on densities

condensers

separate homogeneous mixture using distillation, separates 2 or more volatile liquids

separatory funnel

separate mixtures of heterogeneous mixtures by solubility in polar vs. nonpolar layers

polar = aqueous

non-polar = organic

Buchner Funnel

vacuum filtration

Calculating for Limiting Reactant

BCDS

Balance the chemical equation

Convert the reactants to moles

Divide moles by coefficients

Smallest is the LR

Quantum Numbers

n (principle quantum #): any integer, 1,2,3,4,etc tells us which shell the electron is in. can only go as high as the amount of orbitals the atom has

l (azimuthal quantum #): tells which kind of orbital it is in. s=0, p=1, d=2, f=3

ml (magnetic quantum #): tells which orbital the e- is in, any integer from -l → +l

ms (spin quantum #): one e goes one way, the other the opposite. +1/2, -1/2

paramagnetic

has unpaired e-, attracted to magnets

diamagnetic

all e- are paired, not attracted to magnets

Excited vs. Ground state electron configurations

when filled with electrons, s orbitals are at a higher energy state than the d orbital.

when not filled with electrons, the d orbital is at a higher energy than the s orbital

determines how it is filled when turned to ions

energy of a photon

E = (Planck’s constant)*(frequency) = (Planck’s constant * speed of light) / protons wavelength

planck’s constant = 6.6×10^-34 J*s

speed of light = 3×10^8 m/s

Radiowaves, microwaves, infrared, visible, ultraviolet, x-ray, gamma (highest energy)

roman men invented very unique x-ray guns

Isotopes

atoms of the same element with different numbers of neutrons

Beer-Lambert Law

absorbance = molar absorptivity x concentration x path length

molar abs = how strongly a solute absorbs light at a specific wavelength

Lattice Energy

energy required to completely separate ionic compouns cations from its anions

(cation charge x anion charge) / bond distance

Formal charge

valence e- - one for each dot - one for each bond

bond order

average length of bonds, when multiple contributors are possible

larger the bond order, the stronger the bond

double bonds = 2

single bonds = 1

atomic orbital vs molecular orbital

atomic orbital is the orbitals before forming a molecule

molecular orbital is the orbitals after forming a molecule

molecular geometry

shape when e- not included

electron domain geography

shape when e- are included

2 items around middle atom

sp, 180 degrees, linear

3 things around middle atom

sp2, 120 degrees, trigonal planar

molecular geography is either bent or trigonal planar depending on if there is a lone pair group

3 things around middle atom

sp3, 109.5 degrees, tetrahedral

molecular geometry is either tetrahedral, trigonal pyramidal, or bent

london dispersion forces

temporary dipoles cause momentary attraction between two molecules

dipole-dipole

attraction between two polar molecules

hydrogen bonding

attraction between H atom in one molecule and an F, O, or N of a different atom

ion - dipole

attraction between ions and polar molecules

Ionization energy

energy required to remove an e-

more difficult to remove e- when the electron is smaller b/c they are closer to protons

Electron Affinity

energy produced when an atom accepts an e-

follows trend of EN

Alkali metals

group 1

low ionization energy

very reactive with water, very exothermic

alkaline earth metals

group 2

low ionization energy

react with water, more violent as going down group

halogens

group 17

most EN

high e- affinity

easily reduced, wants e-

noble gases

group 18

unreactive

transition metals

bright colored compounds due to d-orbitals

multiple oxidation states

oxygen group

group 6

O2 is a good oxidizing agent, gives e-

O3 is a better oxidant

metals react to for metal oxides

effective nuclear charge, Zeff

protons ability to suck in e-

more protons mean a smaller ion because e- are sucked in

Nonmetals

dull, low melting point, poor conductor of heat and electricity

metals

metallic, high melting point, good conductor of heat and electricity

metalloids

in between metal and nonmetal

electron shielding

addition of another e- shell

increase size because another shell is added

actinide series

elements #89-103

lanthanum series

elements #57-71

Atoms able to form Hyper Octet

3rd period or lower able to bond more e-

pH

-log [H+]

molality

moles / kg

molarity

mol / L

parallax errors

errors in misreading liquid volumes because of looking at an indirect angle

1 atm equals

1 pascal = 760 torr = 760 mmHg

pressure equals

force / area

Boyle’s Gas Law

as the volume of a gas decreases, its pressure increases

Charles’ Gas Law

volume is proportional to the temperature of a gas

Avogadro’s Gas Law

volume is proportional to the number of gas moles

Combined Gas Law

(P1V1)/(n1T1) = (P2V2)/(n2T2)

Ideal Gas Law

PV=nRT

R= 0.0821 (L*atm / mol*K)

one mole of any gas takes up how much volume

22.4 L

Gas Density

mass/volume

(P*molar mass) / (RT)

Dalton’s Law of Partial Pressures

total pressure is equal to the sum of all the gasses individual pressures

Graham’s Law of Effusion

lighter gas escape (effuse) through a slit more quickly. Heavier gasses effuse more slowly

effusion rate Gas 1 / effusion rate Gas 2 = sqrt(molecular weight Gas 2/molecular weight gas 1)

Strong Intermolecular forces create

higher boiling point

higher viscosity

higher surface tension

lower vapor pressure

Molecular solids

held by dispersion forces, dipole-dipole forces, or hydrogen bonds, fairly soft, low melting point, poor conductors,

ex. methane CH4, sucrose C12H22O11

covalent network solids

held by network of covalent bonds, very hard, very high melting point, poor conductors

ex. C Diamond

Ionic solids

held by attraction between anions and cations, hard and brittle, high melting point, poor conductors

ex. NaCl

metallic solids

held by a delocalized “sea” of electrons flowing around nuclei “island”. soft to very hard, low to very high melting points, good conductors, malleable

ex. all metallic elements

simple cubic unit cell

one total atom inside cell: 1/8 × 8 = 1

body - centered cubic unit cell

two total atoms inside cell: 1 + 8*(1/8) = 2

face-centered cubic unit cell

four total atoms: 8*(1/8) + 6*(1/2) = 4

solid to liquid

fusion

liquid to gas

vaporization

solid to gas

sublimation

gas to solid

deposition

liquid to gas

crystalization

gas to liquid

condensation

fusion, vaporization, sublimation

endothermic, +delta H, increase disorder, +delta S, positive entropy

deposition, crystallization, condensation

exothermic, - delta H, decrease disorder, - delta S, negative entropy

boiling point definition

when vapor pressure equals atmospheric pressure

triple point on phase diagram

equilibrium between all three phases