Chemistry Flashcards Flashcards by Dack Punke

_______________
- The number of protons in the atoms nucleus

Atomic number

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_______________
- The number of protons and neutrons in the atoms nucleus

Mass number

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_______________
- Same number of protons and electrons, but different number of neutrons

Isotope

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_______________
- An atom that has lost electrons

Cation

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_______________
- an atom that has gained electrons

Anion

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True or false : Bohrs model explains emission of specific spectral lines from hydrogen atom

True

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_______________
- are accurate models of where electrons reside outside of nucleus

Orbitals

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The s orbital has ______ orientation(s)
The p orbital has ______ orientation(s)
The d orbital has ______ orientation(s)

1
3
5

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_________ principle
- atomic orbitals are filled from the lowest energy orbital to the highest energy orbital until all electrons are used

Aufbau principle

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____________
- Electrons in the highest energy orbitals

Valence electrons

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____________principle
- only 2 electrons may be placed in one or a little at a time and they must have opposite spins

Pauli exclusion principle

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____________
- orbitals of equal energy must first be filled singly with electrons of the same spin and then paired with electrons of opposite spin

Hund’s rule

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____________
- when an atom absorbs energy, its electrons move to higher energy levels

Energy transition

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____________
- The energy level of an electron prior to energy absorption

Ground state

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____________
- The energy level of an electron after energy absorption

Excited state

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An electron stays at the excited state for a brief period, and then relaxes back to the ground state causing energy to be admitted as _______________

Electromagnetic radiation

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____________ can be produced from both atomic energy, absorption and emission experiments (characteristic of the element, and can be used to determine the identity of an unknown substance)

Spectra

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____________
- experimental procedure to determine precise mass and relative abundance of isotopes in a substance

Mass spectrometry

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____________ operation
- a sample is introduced into the instrument and vaporized
- Vaporize the particles are ionized (creating positively charged radical cations)
- Ions undergo further fragmentation into lower mass ions (occurs through a magnetic field, which separates them by mass)
- Ions leave magnetic field and are detected in the order of highest to lowest mass

Mass spectrometer

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____________
- Fragmentation patterns
- Are unique to the substance
- Provide molecular weight directly
- Molecular formula can be determined

Spectra

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____________
- A property predictable from the elements position in the periodic table

Periodic property

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Atom size (radii) __________ down a group & __________ from left to right across period

Increase
Decrease

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Atomic radii __________ with gain of electrons & __________ with loss of electrons

Increase
Decrease

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____________
- Energy required to remove an electron from an atom or ion and its gaseous state
- values always positive

Ionization energy

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____________ - removal of highest energy electron

First ionization energy

Ionization energy generally __________ down a group & __________ from left to right

Decrease Increase

_______________ - Energy change associated with gain of an electron by an atom in gaseous state - usually exothermic

Electron affinity

Most groups do not exhibit a trend in electron affinity but group 1 elements become more positive down a group Electron affinity generally becomes more __________ from left to right in a period

Negative (exothermic)

_______________ - The ability of an atom to attract electrons in a covalent bond - Values range from 0.7 - 4.0 using the pauling scale (values are unitless)

Electronegativity

Electronegativity _________ down a group & __________ from left to right in a period

Decreases Increases

_______________ - electrostatic attraction between 2 oppositely charged ions (usually a metallic cation & a nonmetallic anion) - Due to lowering of potential energy between oppositely charged ions

Ionic bond

The potential energy of attraction between two oppositely charged ions is estimated by using _______________

Coulomb’s law

_______________ - are energy associated with formation of a crystal of alternating ions from gaseous ions (values are always negative)

Lattice energy

As ions become larger, the △H-lattice becomes less __________

Less negative (less exothermic)

As charges of ions increase, △H-lattice becomes more __________

Negative (more exothermic)

_______________ - when 2 atoms share valence electrons between their nuclei - there potential energies are lowered through electrostatic attraction - Typically nonmetals

Covalent bonds

_______________ - to the drawing, representing covalent bonds between atoms as shared or transferred electrons - Based on the molecular formula

Lewis structures

All elements except for _____ & _____ prefer 8 electrons around their nuclei

H He

When there are several Lewis structures, then ____________ occurs and they can be combined to form a hybrid

Resonance

_______________ - used to determine the best Lewis structure - FC = Atoms Group # - (bonds + unpaired electrons) - “normal valence - (lines +dots)” - a compound’s total charge must equal the sum of all its atoms formal charges

Formal charge

When 2 atoms in a covalent bond have the same electronegativity then the atoms share valence electrons equally so such bonds do not have a dipole moment and are termed _______________

Nonpolar

When atoms in a bond have different electronegativities in a dipole moment, occurs in the covalent bond is termed _______________

Polar

When the difference in electronegativites between atoms in a bond is very large then an __________ interaction occurs because electrons are transferred to the more electronegative atom

Ionic

_______________ theory - one of several techniques that can be used to predict the shapes of molecular compounds - based on the idea that electrons with similar charges repel each other - when only bonding electron pairs are considered than 5 shapes are predicted - other shapes are predicted when a pair of bonding electrons is replaced with a pair of non-bonding electrons

Valence Shell Electron Pair Repulsion theory VSEPR

When 1 bonding group of the principle tetrahedral shape is replaced with a lone pair. The shape is now called _______________ and has bond angles of _________

Trigonal pyramidal ~107 degrees

When 2 bonding groups of the principal tetrahedral shape is replaced with two lone pairs in the shape is called _______________ and had bond angles of _________

Bent ~105 degrees

True or false : Polarized bond exist in a molecule than the overall molecule may or may not be polar because the shape in the orientation of dipole moment can be used to predict Molecular polarity

True

_______________ theory - approach to predicting length and strength of covalent bonds qualitatively and molecular compounds - also predicts 3D shapes of molecules 3 basic principles - Overlap of atomic orbitals containing unpaired valence electrons - Localization of valence electrons in the orbital overlap region between atoms - Formation of hybrid orbitals from atomic orbitals to optimize orbital overlap between bonding atoms

Valence bond theory

___________ bonds - form by the end-to-end overlap of atomic and hybrid orbitals containing unpaired electrons - bonded atoms share electrons between them

Sigma bonds

___________ bonds - form by side to side, overlap of atomic orbitals, usually p orbitals -are longer & only about 3/4 as strong as sigma bonds - can form only in conjunction with sigma bonds (cannot exist without a sigma bond)

Pi bonds

_______________ - compounds differ in some ways, but have same molecular formula

Chemical isomers

_______________ - same molecular formula, but differ in the way the atoms in the molecule are bonded to each other

Structural isomers “Constitutional isomers”

_______________ - same molecular formula and connectivity a differ in the way the atoms are arranged - cannot be interconverted by sigma bond rotation (“single bond”)

Stereoisomers

_______________ - usually a carbon atom that is sp3 hybridized & has 4 different atoms or groups of atoms attached to it

Chirality Center

Stereoisomers have 2 categories _______________ _______________

Enantiomers Diastereomers

_______________ - nonsuperimposable mirror images of each other - always come in pairs (the left and right handed isomers of a compound) - always contain at least 1 chirality center - a pure enantiomer is optically active & rotates plane-polarized light

Enantiomers

_______________ - not mirror image stereoisomers of each other - includes all forms of stereoisomers except enantiomers

Diastereomers

Process of R and S assignment of absolute stereochemistry to chirality centers - each of 4 groups bonded to chiral carbon in chirality center is assigned a priority - priorities are assigned using the _____________________ protocol - lowest priority group is position behind chiral carbon, leaving the remaining high priority groups in a trigonal planar configuration. If priorities of groups around the chiral carbon are 1 to 2 to 3 in a clockwise direction then the center is designated R & and if the priorities are counterclockwise in the center is designated S

Cahn-Ingold-Prelog (CIP) protocol

Stereoisomers of certain organic compounds (specifically alkenes) occur as a type of diastereomer & can be distinguished as ________ or ________

Cis- Trans-

__________ configuration - 2 atoms of the same type are on opposite sides of double bond

Trans- configuration

___________ configuration - 2 atoms of the same type are on the same side as of double bond

Cis- configuration

_______& ________ assignment - common protocol to distinguish alkene stereoisomers

E (entgegen = opposite) Z (zusammen = together)

E and Z designations are most commonly used when there are no like groups attached to the double bond, but they can be used to indicate the stereochemistry of any alkene. The procedure for assigning E and Z to a specific stereoisomer (use C-I-P prioritization rules) - When highest priority groups are on opposite sides of the double bond, the isomer is designated as _____ - when highest priority groups are on the same side of the double bond, it is designated as _____

E Z

_______________ - heat required to raise the temperature of a substance by 1°C

Heat capacity

_______________ - heat required to raise the temperature of 1 g of a substance by 1°C

Specific heat capacity

_______________ - temporary structural isomerism to study energy changes because sigma bonds have freedom of rotation (parts of molecule can move many ways)

Conformational analysis

_______________ - 2 different conformational if structures of ethane

Sawhorse structures

____________ conformations of ethane - all H aligned & high energy due to torsional strain ____________ conformations of ethane - no H aligned & low energy

Eclipsed conformations Staggered conformations

A ___________________ , useful in alkane stereochemistry, visualizes the conformation of a chemical bond from front to back, with a line representing the front atom and a circle representing the back carbon. The carbon atom at the front is called proximal, while the atom at the back is called distal.

Newman projection

In cyclohexane conformations the lowest energy conformation is called the _________ (with almost no ring strain)

Chair

Chair conformation has 2 different types of substitute bonding positions where H & other substitutes are attached to ring. These positions are ________ (bonds, extend directly above & below the ring) and ____________ (bonds are oriented at ~ 45° angles around the equator of the ring)

Axial Equatorial

Any chair conformation with a substitute larger than an H-atom has lower energy (more stable) with substitute in equatorial position, so lowers ____________

Steric strain

True or false: Gases differ from the condensed phases of liquids & solids in a number of ways - Gas volume changes greatly with pressure - Gas volume changes greatly with temperature - Gases have low viscosity - Gases are always miscible with each other

True

True or false: Ideal gases do not exist. A true ideal gas would be made up of molecules that have no interaction with each other (no attractive forces) and zero volume. Helium is the closest to an ideal gas.

True

Measurable parameters of ideal gases can be estimated from _____________ law _____________ law _____________ law

Charles law Boyles law Avogadro’s law

_______________ - volume of gas directly proportional to temperature - P and n held constant

Charles law

_______________ - volume of gas inversely proportional to pressure - T and n held constant

Boyles law

_______________ - volume of gas is directly proportional to amount of gas - P and T held constant

Avogadro’s law

____________ law - PV = nRT - Basic gas relationships can be combined to give a single law (Charles, Boyles, & Avogadro’s)

Ideal gas law

_______________ - models, an ideal gas as a collection of point particles constantly in motion & undergoing completely elastic collisions - Explains Avogadro’s law - For any ideal gas at standard temperature and pressure (STP) [1 mole gas = 22.4 L]

Kinetic-molecular theory

_______________ - any gas mixture, each gas ask independently so that any overall property of the mixture is the sum of the properties of the individual components - Some of the individual gas pressures (partial pressures) must equal total pressure (P-total = P-a + P-b + P-c …..) - if total pressure of mixture is known, partial pressure of any component can be determined

Dalton’s law of partial pressures

_____ gas behavior - Real gases deviate from ideal gas properties to different degrees under various conditions - At high pressures (>20 atm) the molar volume is greater than that of ideal gas - At low temperatures (<200K), the stronger attractions between gas particles lower number of collisions on surface of a container, lowering pressure compared to ideal gas

Real

The _____________ equation is used to correct for high pressure & low temperature effects - P + a(n/V)^2 • (V - nb) = nRT - P + a(n/V)^2 : corrects for intermolecular forces - (V - nb) : correct for molar volume (a & b are constants for specific gases)

Van der Waal’s equation

__________ - A condensed phase of matter - atoms & molecules packed as closely as in a solid, but can move relative to each other - A fixed volume but not a fixed shape (shape of its container) - Properties : vapor pressure, boiling point, viscosity, & surface tension

Liquids

__________ - attractive & repulsive forces between atoms and molecules in a liquid - Hold condensed phases of matter together - Ion-dipole, H bonds, dipole-dipole, & London dispersion

Intermolecular forces

__________ - between ion and oppositely charged end of polar molecule

Ion dipole

__________ - very strong dipole-dipole attractive force between a hydrogen atom bonded to a highly electronegative atom on a neighboring molecule - “FON”

Hydrogen bonding

__________ - exhibited by polar molecules - due to uneven distribution of electrons

Dipole-dipole

__________ - exhibited by all atoms and molecules - Due to instantaneous polarization of their electron clouds

London dispersion

__________ - SI unit used to convert between particles of a substance and mass - 1 mall of a substance = number of atoms in 12 grams of carbon-12 - Numerical value for number of particles in a mole of anything is called Avogadro’s number (6.0221421 x 10^23)

Mole

__________ - mass in grams of one mole of an element - Equals the atomic mass of the element in atomic mass units (amu)

Molar mass

__________ - lowest whole number ratio of elements in a compound

Empirical formula

__________ - actual number of atoms of each element in the compound

Molecular formula

__________ - shows all the atoms present in the compound and how they are bonded to each other - Can be shown in both 2-D and 3-D space

Structural formula

3 categories of chemical reactions ____________ ____________ ____________

Precipitation Acid base Oxidation reduction

__________ - 2 soluble ionic compounds react in aqueous phase to produce 1 or more insoluble ionic compounds called precipitates (the product) - reaction generally follows only 1 pattern called double replacement (AB + CD —> AD + CB) - when metal ions switch counter ions either AD or CB may be a precipitate (it will be denoted as solid)

Precipitation

Water _________ rules for ionic compounds predict formation of precipitate

Water solubility rules

______________ (neutralization) - combination of an acid and a base in aqueous phase to produce water and an ionic compound (salt), and sometimes a gas - Acid = proton donor & Base = proton, acceptor

Acid base reactions

________________ reactions - transfer of electrons between reactant atoms - Atoms of 1 element lose electrons & atoms of 1 element gain electrons

Oxidation reduction reactions (redox)

Most common reaction patterns for redox reactions : ____________ : A + B —> C ____________ : C —> A + B ____________ : A + BC —> AC + B ____________ : CxHy + (x + 1/4y)O2 —> xCO2 + 1/2yH2O

Addition Decomposition Single displacement Combustion

To determine if electron transfer has occurred, atoms in reactants & products are assigned _______________

Oxidation numbers

______________ - The relationship between amount of reactants & products in a balanced chemical equation

Stoichiometry

A reaction unit factor (mole : mole ratio) is based on a _______________

Balanced equation

______________ - reactant in balanced stoichiometric equation that is used up first - once reactant used up then reaction stops & no more product is formed

Limiting reactant (reagent)

______________ - greatest possible amount of a specific product that can be obtained from a specific chemical reaction - always a calculation based on a stoichiometric relationship obtained from a balanced equation

Theoretical yield

______________ - yield of a specific product obtained from a specific chemical reaction - Always based on an actual laboratory experiment, process, or personal experience

Actual yield

______________ - a measure of how efficient a reaction is in producing a specific product - Always <100% - (Actual yield / Theoretical yield) x 100%

Percent yield

______________ - Study of the relationship between chemical processes & energy - most common units are the joule (J) and calorie (cal)

Thermochemistry

______________ - General study of energy and its inter-conversions - Energy can be neither created nor destroyed & is always conserved

Thermodynamics

______________ - The total energy of the universe is constant.

First law of thermodynamics

______________ - sum of Kinetic Energies & Potential Energies of all particles of a system

Internal energy (E)

True or false : Estimating a change in E requires only initial and final values

True E = E-final - E-initial

Any thermodynamic process, energy loss & energy gain are defined in terms of the __________ and the __________

System Surroundings

Overall internal energy change of a system involves 2 types of energy changes : ____________ ____________

Heat (q) Work (w)

______________ - A special type of thermal energy, or heat, that is a state function - The change in H of a system at constant pressure is the sum of its △E & the product of its pressure (P) & change in volume (△V) - △H = △E + P△V

Enthalpy

If the heat/work equation and the enthalpy equation are combined then enthalpy is shown as _______________

Heat at constant pressure (qp)

__________ process - △H is negative (-) - System is losing heat to surroundings

Exothermic process

____________ process - △H is positive (+) - System is absorbing heat from surroundings

Endothermic process

Breaking chemical bonds is an ___________ process

Endothermic (energy absorbed)

Forming chemical bonds is an _____________ process

Exothermic (energy released)

____________ - an experimental technique that uses a Calorimeter to measure heat change for a process (often a chemical reaction)

Calorimetry

____________ - A device used to measure heat, released or absorbed by a physical or chemical process that takes place inside it - Process is the system and the calorimeter is the surroundings

Calorimeter

______________ calorimetry - measurement of heat changes of a system using a bomb calorimeter at constant volume - Used to estimate △E of a system (qv = △E)

Constant-volume Calorimetry

_______________ calorimetry - measurement of heat changes of a system using an open calorimeter at constant pressure - Used to estimate △H of the system (qp = △H)

Constant pressure Calorimetry

__________ - A measure of the randomness or disorder of a system - S = k ln W

Entropy

_________________ - for any spontaneous process the entropy of the universe increases

The second law of thermodynamics

____________ - A process that occurs by itself under natural conditions

Spontaneous process

If △S-univ > 0 , a process will be ______________

Spontaneous

An ____________ process increases △S-surr

Exothermic

An ____________ process decreases △S-surr

Endothermic

________________ - The entropy of a perfect crystal at absolute zero temperature is zero

Third law of thermodynamics

_______________ - entropy values at standard states - Used to calculate standard entropy changes for chemical reactions

Standard molar entropies

_______________ - State function that combines a processes enthalpy and entropy changes - Indicates a reactions spontaneity

Gibbs free energy (G)

△G < 0 means process is ______________

Spontaneous ( exergonic)

△G > 0 means process is ______________

Nonspontaneous (endergonic)

△G = 0 means process is ____________

At equilibrium

____________________ - at a given temperature, chemical reaction reaches a state at which a particular ratio of reactant & product concentrations has a constant value

The law of chemical equilibrium

____________________ - concentration of the product(s) raised to the balanced equation coefficients divided by the reactant(s) raised to their balanced equation coefficients, when the overall process has reached equilibrium

Equilibrium constant (Kc)

____________ - same ratio as K except overall reaction need not be at equilibrium

Reaction quotient (Q)

If Q < K , the reaction will progress toward ____________ until equilibrium is established

Products

If Q > K , the reaction will progress toward ___________ until equilibrium is established

Reactants

If Q = K , the reaction is at ____________

Equilibrium

Reaction quotient (Q) it’s not a constant & can’t have any value depending on product: reactant ratio - if Q = 0 then reaction has only __________ - If Q = ∞ then reaction has only __________ - If Q = 1 then reaction has equal product and reactant concentrations

Reactants (no products) Products (no reactants)

_______________ - if a system at equilibrium is disturbed, position of equilibrium shifts to minimize disturbance

Le Chatelier’s principle

Effect of concentration changes on equilibrium (at constant temp) - Shift away from side where chemicals are ______ & shift toward side where chemicals are _______ - Adding a reactant __________ amounts of other reactants & ________ amount of products, until a new equilibrium is reached (value of K does not change) - Removing a product ________ amounts of other products & __________ amount of reactants, until I knew equilibrium is reached (value of K does not change)

- Added & Removed - Decreases & Increases - Increases & Decreases

Effect of volume changes on equilibrium : - when pressure is increased, equilibrium shifts towards the side with ________ molecules to decrease the pressure until new equilibrium - when pressure is decreased, equilibrium shifts toward the side with ________ molecules to increase the pressure until new equilibrium - Value of K does not change of temperature is constant

Fewer More

True or false Effect of temperature changes on equilibrium (temp change does affect K) : - Increasing temperature of endothermic reaction is like adding heat to the reactant side of the chemical equation - Adding heat to an endothermic reaction, decreases concentrations of reactants and increases concentrations of products - Increasing temperature of an exothermic reaction is like adding heat to the product side of the chemical reaction - Adding heat to an exothermic reaction, decreases concentrations of products and increases concentrations of reactants

True

____________ favored reaction - process moves spontaneously (△ G < 0) toward products until equilibrium is reached (K > 0) - More products than reactants

Product favored reaction

__________ favored reaction - process moves spontaneously (△G < 0) toward products until equilibrium is reached (K < 1) - More reactants than products

Reactant favored reaction

_______________ - a homogenous mixture of 2 or more substances - often just 2 components : solvent and solute

Solution

_______________ solution - solvent still has a capacity for more solute molecules or ions - If more solute is added, solute will dissolve & its concentration will be higher

Unsaturated solution

_______________ solution - solvent’s capacity for solute molecules or ions has been reached - If more solute is added, solute will not dissolve and concentration in solvent remains the same

Saturated solution

_______________ solution - solvents capacity exceeded - Due to unusual conditions, excess solute remains dissolved (related to entropy) - A slight disturbance of system usually leads to precipitation of excess solute

Supersaturated solution

_______________ - an equilibrium constant for dissolving a slightly soluble ionic compound in water - Values range from ~1x10^-4 to 1x10^-70 - calculated from an ion–product expression for a slightly soluble salt

Solubility product constant (Ksp)

_______________ - if 2 solutes, 1 highly soluble & 1 slightly soluble share a common ion, the common ion decreases solubility of slightly soluble compound

Effect of a common ion on solubility (common ion effect)

_______________ - solubility of ionic compounds that contain an anion from a weak acid increases when pH of the solution is low (acidic)

Effect of pH on solubility

_______________ - A species consisting of a central metal ion bonded to molecules and/or anions called ligands

Complex ions

For an ionic compound with a transition metal cation, that forms complex ions, solubility increases in presence of _____________ that form a complex with the cation

Lewis bases (e.g. NH3)

Brønsted-Lowry acid definition of an acid is a proton ________ (H+)

Donor

Acid strengths are relative to their ability to donate ___________

Protons (H+)

__________ - donate all their protons to water to form large amounts of hydronium ions (H3O+) - At equilibrium, almost none of the original acid is unreacted

Strong acids

_______________ - donate only some of their protons to water to form relatively small amounts of hydronium ions (H3O+) - At equilibrium, most of the original acid is unreacted

Weak acids

_______________ - an equilibrium constant that defines extent of a weak acids dissociation

Acid ionization constant (Ka)

_______________ - an equilibrium constant that defines extent that water acts as a weak acid by donating a proton to another water molecule to form minute, amounts of hydronium ions and hydroxide ions

Water autoionization constant (Kw)

Kw relationship : [H3O+] > [OH-] —> ______solution [H3O+] < [OH-] —> ______solution [H3O+] = [OH-] —> ______solution

Acidic Basic Neutral

_______________ - A negative, base 10 log scale of weak acid ionization constants

pH scale

Brønsted-Lowry definition of a base is a proton _____________ (H+)

Acceptor

_______________bases - always metallic salts of hydroxide anion - if soluble in water, dissociate almost completely into aqueous solution

Strong bases

_______________ bases - do not directly contain hydroxide anions but generate minute amounts of hydroxide anion

weak bases

_______________ - equilibrium constant that defines extent of a weak bases formation of OH-

Base ionization constant (Kb)

_______________ - a negative base 10 log scale of weak bases ionization constants

pOH scale

Anions of weak acids (the acids conjugate base) act as ____________

Weak bases

Anions of strong acids (the acids conjugate base) are __________

Neutral

Cations that are counterions of strong bases (OH-) are ____________

pH neutral

Cations of weak bases (the bases conjugate acid) act as ____________

Weak acids

Small highly charged metal cations form weakly ___________ solutions

Acidic

Acid base properties of salt solutions : - __________ solutions from salts with Anions of Strong Acids & Cations of Strong Bases - __________ solutions from salts with Anions of Strong Acids & Cations of Weak Bases - __________ solutions from salts with Anions of Weak Acids & Cations of Strong Bases

Neutral Acidic Basic

_______________ - a solution of water-soluble compounds that resists pH changes

Buffer

_______________ - solutions with 2 species that share a common ion resist becoming more acidic (buffering effect)

Common ion effect

_______________ - procedure for determining concentration of a solution using another solution of known concentration

Titration

_______________ titration - to estimate an unknown acids concentration, a base solution of known concentration is added until the acid and base have just completely reacted. The reaction is complete when an added indicator changes color (end point)

Acid base titration

_______________ - Point in a titration, at which number of moles of a substance of known concentration is equal to number of moles of unknown substance

Equivalence point

The equivalence point is best estimated from a ____________

Titration curve - the inflection point of curve represents the EP

_______________ - Study of rate at which chemical transformations occur - Change in the concentration of reactants or products relative to time usually used to estimate reaction rates

Chemical kinetics

_______________ - rate of change of reactant or product concentrations during a defined time interval

Average reaction rates

Average rates ____________ as the reaction progresses from reactants to products due to the ever increasing rate of reverse reaction and continues until equilibrium is reached

Decreases

_______________ - The rate at a particular time during a reaction - As with the most average rates, these rates decrease as the reaction progresses

Instantaneous rates

Most important instantaneous reaction rate is the ___________ rate

Initial rate

_______________ - allow estimation of chemical reaction rates as a function of changing reactant concentration, assuming a constant temperature

Rate laws

_______________ components - must be determined experimentally - Initial rates can be determined from initial reactant concentrations - By using initial rates from several experiment, reactant orders are determined - Known reaction rate in reactant order used to calculate value of K

Rate law components

_______________ - When simple differential rate laws for a single reactant decomposing into products are integrated over time, new relationships are obtained and relating concentrations of reactants to time

Integrated rate laws

_______________ - Time required for reactant concentration of a reaction to drop to half of its initial concentration

Half life

_______________ equation - used to estimate the effect of temperature changes on a reaction rate constant (k)

Arrhenius equation

_______________ plot - A graph of the natural log of rate constant versus inverse of the temperature in K - Yields a straight line

Arrhenius plot

____________________ equation - simplified equation that is used to estimate reactions Ea using rate constant data at 2 different temperatures

Two point Arrhenius equation

_______________ diagram - shows potential energy of a reaction as it progresses

Reaction energy diagram

_______________ - sequence of elementary reaction steps (singular molecular event) that explains how reactants are transformed into products - rate law for an elementary reaction is determined from its stoichiometry

Reaction mechanism

_______________ - step that limits how fast overall reaction can progress - Elementary steps of a mechanism do not necessarily have same rate and often one step is slower & controls rate of overall process

Rate determining step

Correlating a reaction mechanism to a rate law —> mechanism must meet criteria : - Elementary steps must __________ two overall balanced equation and cannot be fewer reactants or products than in balanced equation - Elementary steps must be physically reasonable and most involved one or two species - Mechanism must correlate with rate law and must support experimentally & independently determined rate laws

Add up

_______________ - Study of relationship between a chemical change and electrical work

Electrochemistry

_______________ - System that incorporates a redox reaction to produce electrical energy (spontaneous process) or utilize it (non-spontaneous process)

Electrochemical cell

_______________ reactions - transfer of electrons between reactant atoms

Oxidation reduction reactions

_______________ - object that conducts electricity between the cell and surroundings

Electrode

_______________ - mixture of ions (usually an aqueous solution) that are involved in an electron flow process (redox reaction)

Electrolyte

_______________ - electrode where oxidation a half reaction takes place - negative

Anode

_______________ - electrode where reduction half reaction takes place - positive

Cathode

_______________ cell - produces electrical current from a spontaneous redox reaction

Voltaic cell

_______________ - compartment were components of each of cells redox half reactions are housed

Half cell

_______________ - pathway by which counterions flow between the half cells while not allowing components to mix

Salt bridge

_______________ notation - Oxidation half cell is on the left and reduction half cell is on the right - components of cell appear in same order as half cells with electrodes on the outside - Double lines, separate half cells and represent salt bridge - Counter ions associated with the salt bridge are not shown

Voltaic cell notation

_______________ - potential difference between half cells - Driving force for electron flow

Cell potential

____________ (SHE) - Half cell potential cannot be measured directly, so a particular half cell is arbitrarily assigned potential of 0 V - and all other half cell potential‘s are measured relative to this standard

Standard hydrogen electrode

E-cell values are used to predict redox reaction ____________

Spontaneity

E-cell > 0 reaction is _______________

Spontaneous

E-cell < 0 reaction is _______________

Nonspontaneous

_______________ - uses electrical energy to drive non-spontaneous redox reactions

Electrolysis

_______________ cell - similar to voltaic cell that can drive nonspontaneous redox reactions - Electrodes (oxidation at anode & reduction at cathode) - Difference from voltaic cell is an external electrical voltage source - Voltage source is positive terminal is connected to anode which draws electrons from anode & negative terminal is connected to cathode which supplies electrons to cathode

Electrolytic cell