Chem yay

Accuracy

how close a measurement is to the true value

Precision

a measure of how close a series of measurements are to one another

Density

D=m/v

Percent Error

the absolute value of the error divided by the accepted value, multiplied by 100%

Intensive

It is not related to the amount of the object.

SI System

Prefixes are based on the power of 10

Mixture

A combination of two or more substances that are not chemically combined

Homogeneous: uniform composition; solution

Heterogeneous: no uniform composition

Pure Substances

Can NOT be physically separated

Element: can't be chemically decomposed

Compound: can be chemically decomposed

Heterogeneous

Colloids: medium sized, tyndall effect, particles don't settle

Suspension: large particles, tyndall effect, particles will settle

Compound

Composed of 2 or more elements in a fixed ratio (properties of individual elements)

Element

composed of identical atoms

Chemical Property

substance's ability to react with other substances (react with air/water, catch fire)

Physical Changes

occurs without changing the identity of the substance (changes in shape/size/color)

Law of Definite Composition

A given compound always contains the same, fixed ratio of elements

Chemical Changes

causes the identity of a substance to change; something new is formed

Law of Multiple Proportions

elements can combine in different ratios to form different compounds

Physical Property

description of an object using the 5 senses.

Neutron

no charge (neutral), in the nucleus, two downs, one up, three quarks

Ion

Element with a charge (+/-)

Metals: positive, cations (lose electrons)

Non-metals: negative, anions, (gain electrons)

Beta (type of decay)

minus 1 charge, fast & light, changes neutron into proton.

Proton

positive charge, in the nucleus, two ups and one down, determine atom's identity

Radioisotope

isotope with an unstable nucleus, causing it to break down and release radioactivity

Gamma (type of decay)

• waves, not particles

• no mass or charge

• high penetrating power

• don't directly ionize

Alpha (type of decay)

• 2 protons and neutrons

• slow and heavy

• low penetrating power

• ionize: pull electrons from other atoms strongly

Isotope

Atoms of the same element that have different numbers of neutrons; causes a difference in mass

Electron

negative charge, valence shell, bonds, responsible for chemical properties

Ideal Gas Law

PV = nRT

• moles are constant

• must be in Kelvin, liters, atm, moles

• R = 0.0821 Lxatm/molxK

Boyle's Gas Law

P1 x V1 = P2 x V2

• temperature is constant

• inverse relation (pressure increases = volume decreases)

Charles's Law

V1 x T2 = V2 x T1

• pressure is constant

• Direct relation (increased temp = increased pressure)

Gay-Lussac Law (Amonton Law)

P1 x T2 = P2 x T1

• volume is constant

• Direct relation (increase temperature = increase pressure)

Combined Gas Law

P1 x V1 x T2 = P2 x V2 x T1

• moles are constant

Dalton's Law

Pt = P1 + P2 + P3

(moles gas / total moles) x Pt = Px

Avogrado's Law

V1 x n2 = V2 x n1

• pressure and temperature are constant

• direct relation (moles increase = volume increase)

Graham's Law of Effusion

rate1/rate2 = √MM2 / MM1

• lighter gas = faster it will diffuse

• inverse relation

Pressure Constants

14.7 psi

101.3 kPa

760 torr

760 mmHg

1 atm

1 bar

Temperature

• K = C + 273

• C = K - 273

• F = (C x 9/5) + 32

• increased temp = increased velocity = increased pressure

• higher temp = more KE (particles move faster)

STP Constants

Volume: 22.4L

Pressure: 1 atm

Temperature: 273K

n: 1 mole

R: 0.0821 L·atm/mol·K

Relationships

• P increases = V decreases

• T increases = V increases

• T increases = P increases

• n increases = V increases

Fission

The splitting of an atomic nucleus to release energy.

Fusion

Creation of energy by joining the nuclei of two hydrogen atoms to form helium.

Half Life

The time required for one half of the atoms of a radioisotope to emit radiation an decay products

Amount Remaining = initial amount * (1/2)^2

Aufbau Principle

Electrons added one at a time to the lowest energy orbital available until all of the atom's electrons are accounted for

Pauli Exclusion Principal

An atomic orbital may describe at most two electrons, each with opposite spin direction.

Hund's Rule

states that single electrons with the same spin must occupy each equal-energy orbital before additional electrons with opposite spins can occupy the same orbitals

EM spectrum

In Order of Frequency:

-Radio

-Microwave

-Infared Rays

-Visible Light

-UV Rays

-X-Rays

-Gamma Rays

Quantum

the minimum amount of energy that can be gained or lost by an atom

Electron Ground State

lowest energy state

Electron Exited State

Wants to be at ground level, loses gained energy

Absorption Spectra

absorbs energy -> leaves -> back down (light absorbed); dark line

Quantum Numbers

n (principal quantum number), l (angular momentum), ml (magnetic), ms (spin)

Atomic Radius

size of an atom (nucleus to outermost electron)

Electronegativity

• ability of an atom to attract electrons

• decrease down a group (atomic size increases)

• increases across a row (atomic size decreases)

Ionic Radius

• size of atom when its an ion

• cations = more attraction

• anions = not as much attraction

• same trends as atomic radius

Emission Spectra

falls backs to ground state energy released; released photons (bright line)

Speed of light

c = wavelength * frequency

Reactivity

Tendency of an atom to react

• Metals: lose electrons; based on lowest IE = high reactivity

• Nonmetals: gain electrons; based on high EN = high reactivity

Naming Covalent Compounds

mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca

Chemical bond

the sharing to transfer of electrons to obtain a stable configuration. Ex. Ionic, Covalent, Metallic

Metallic (Intramolecular force)

Metal and Metal

Properties: ductile, malleable, solid conductors

Alloys: mixture of metals combines for desirable properties

EM Wave Patterns

long wavelength = low frequency and not intense

short wavelength = high frequency = high energy

Ionization Energy

the energy required to remove an electron from an atom

• decreases down a group: further from the nucleus = more movable

• increases across a row: closer to nucleus = harder to move

Ionic (Intramolecular force)

metal and non metal; high melting points, conductivity, brittle, no odor

Covalent (Intramolecular force)

nonmetal and nonmetal

Nonpolar: equal electron sharing

Polar: unequal electron sharing; higher boiling point

Periodic Law

The elements, when listed in order of their atomic numbers, fall into reoccurring groups, so that elements with similar properties occur at regular intervals.

Kernal Method

[Noble Gas closest prior to element] remaining electron configurations

Miscible

liquid substance that is soluble in another liquidNa

Nature of Solutes:

• spread evenly in solution

• cannot be separated by filtration or evaporation

• solution appears transparent

How to speed up solute dissolving:

• increase temperature

• use smaller size solute particles

• stir the solution

Molality

m=moles of solute/kg of solvent

Molarity

M= moles of solute/ L of solution

pH

pH=-log[H+]

Measures the concentration of H+ ions

pOH

Defines basicity of a solution

pOH=-log[OH-] cannot be less than 7, so subtract from 14 if less.

Hyrdolysis of Salts

Strong Acid + Strong Base -> Neutral Salt

Strong Acid + Weak Base -> Acidic Salt

Weak Acid + Strong Base -> Basic Salt

Acid-Base Titration

Normality of Acid * Volume of Acid = Normality of Base * Volume of Base

A process of using a solution of known concentration to determine the concentration of an unknown solution

Molarity by Dilution

M1 * V1=M2 * V2

Dilution: process of preparing a less concentrated solution from a more concentrated one

pH chart

A chart that tells if something is an acid, a base, or neutral.

Normality

Molarity * Positive oxidation number

Arrhenius

Acids: produce H+

Bases: produce OH-

Bronsted-Lowry

Acids: donate H+

Bases: accept H+

Lewis

Acids: can accept an electron pair

Bases: can donate an electron pair

Conjugate Base

what is left after an acid gives up a proton

Naming Acids

IF anion does NOT contain oxygen = Hydro + root name + ic

IF anion DOES contain oxygen = ate becomes becomes ous

Electrolytes

Substances that break up (dissociate) water to produce ions capable of conducting (ionic)P

Percent by Mass

(mass of solute / mass of solution) x 100

colligative properties

• increase solute = decrease vapor pressure

• increase solute = decrease freezing point

• increase solute = increase boiling point

Freezing/Boiling Point Formula

ΔTf = (Kf)(m)(i)

ΔTb = (Kb)(m)(i)

Properties of Acids

• pH < 7

• taste sour

• react with metals

• turns litmus paper red

Properties of Bases

• pH > 7

• taste bitter

• slippery/soapy feeling

• turn litmus paper blue

Indicators

Chemicals which change colors when they are put into acids or bases

Unsaturated

more solute can dissolve (below the line)

Saturated

contains the max amount of solute (on the line)

Supersaturated

more solute than theoretically possible (above the line)

Neutralization Reaction

A + B --> S + W

Equilibrium

Can go through forward AND backwards reactions

Acid Equilibrium

HA <--> H+ + A-

Strong acids = no HA left and Ka is undefined

Base Equilibrium

B + H2O <--> HB+ _ OH-

Strong bases = no B left and Kb is undefined

Precipitate

an insoluble solid formed when two solutions mix

NASL

Needed electrons, available electrons, shared electrons, lone electrons