Chemistry Unit 3 and 4

Absolute alcohol

common name for high purity ethanol and ethyl alcohol

absolute error

an expression of the uncertainty or inaccuracy of a measurement

absorbance

measure of the amount of light absorbed by a sample

acid

a chemical species that accepts electrons or donates protons or hydrogen ions

actinides

elements 90 (thorium) through to 103 (lawrencium)

activation energy

the minimum amount of energy needed for a chemical reaction to occur

actual yield

the quantity of product experimentally obtained from a chemical reaction

aliphatic amino acid

amino acid that has an aliphatic side chain

alkaline

an aqueous solution with a pH greater than 7.

alkene

a hydrocarbon containing a double carbon-carbon bond

allotrope

a form of an elemental substance

alloy

substance made by melting two or more elements, at least one of which must be a metal

alpha decay

spontaneous radioactive decay which produces an alpha particle or helium nucleus

amide

functional group containing a carbonyl group linked to a nitrogen atom.

amine

compound in which one or more hydrogen atom in ammonia is replaced by an organic functional group.

amino acid

an organic acid containing a carboxyl (-COOH) and amine (-NH2) functional group along with a side chain

amphiprotic

species that can both accept and donate a proton or hydrogen ion

anion

an ion with a negative electrical charge

anode

electron where oxidation occurs; positive charged anode

aqueous

describes a system containing water

balanced equation

chemical equation in which the number and type of atoms and the electric charges are the same on both the reactant and product sides of the equation.

basic

alkaline or having a pH > 7

beta decay

type of radioactive decay that results in spontaneous emission of a beta particle

biochemistry

chemistry of living things

boiling point

temperature at which a liquid's vapor pressure is equal to the external gas pressure

bond

a chemical link formed between atoms in molecules and molecules and ions in crystals

Boyle’s law

ideal gas law that states the volume of a gas is inversely proportional to its absolute pressure, assuming constant temperature.

branched chain alkane

an alkane with alkyl groups bonded to the central carbon chain

calorimeter

instrument designed to measure the heat flow of a chemical reaction or physical change.

carbonate

an ion consisting of one carbon bonded to three oxygen atoms (CO32-) or a compound containing this ion

Carbonyl

functional group consisting of a carbon atom double bonded to oxygen, C=O

catalyst

substance that increases the chemical reaction rate by decreasing its activation energy

cathode

electrode where reduction occurs; usually the negative electrode

cation

ion with a positive electrical charge

Charles's law

ideal gas law that states the volume of an ideal gas is directly proportional to absolute temperature, assuming constant pressure.

chemical equilibrium

state of a chemical reaction where the concentration of the reactants and products remains stable over time.

chromatography

group of techniques used to separate mixture components by passing the mixture through a stationary phase.

combustion

chemical reaction between a fuel and oxidizer that yields energy (usually heat and light)

concentration

an expression of the quantity of a substance in a defined volume

Conductor

material that permits the flow of energy (e.g., electrical conductor, thermal conductor).

conjugate acid

HX, a compound differing from a base X by a proton

conjugate base

the species that gains a proton in an acid-base reaction

Covalent bond

chemical link between atoms or ions in which the electron pairs are more or less evenly shared between them.

Dalton’s Law

relation stating the total pressure of a gaseous mixture equals the sum of the partial pressure of the component gases.

daughter isotope

product formed after a radioisotope (the parent) undergoes radioactive decay

decomposition reaction

chemical reaction in which a single reactant yields two or more products

density

mass per unit volume

diffusion

movement of a fluid from a region of higher concentration to a lower concentration

dilute

solution containing a small amount of solute relative to the amount of solvent.

Dipole

a separation of electrical or magnetic charges

disaccharide

carbohydrate formed when two monosaccharides bond, removing a molecule of water from their structure.

double bond

chemical bond in which two electron pairs are shared between two atoms.

ductile

able to be stretched into a wire without breaking

efflorescence

process by which a hydrate loses water of hydration

elasticity

physical property of matter describing the ability to return to original shape after deformation

electrochemistry

scientific study of reactions and species formed at the interface between an electrolyte and a conductor, where electron transfer occurs.

electrode

the anode or cathode of an electrical cell

electrolysis

passage of direct current through an ion-conducting solution, producing a chemical change at the electrodes

electronegativity

roperty of an atom that reflects its ability to attract electrons in a chemical bond

electroplating

process of adding a metal coat to a material by using a reduction reaction

element

a substance that cannot be subdivided using chemical means; identified by the number of protons in its atoms

empirical formula

formula that shows the ratio of elements in a compound, but not necessarily their actual numbers in a molecule.

endothermic

process which absorbs thermal energy from its environment

enthalpy

thermodynamic property of a system that is the sum of the internal energy and the product of pressure and volume

entropy

measure of the disorder of a system

equilibrium constant

ratio of the equilibrium concentration of products raised to the power of their stoichiometric coefficients to the equilibrium concentration of the reactants raised to the power of their stoichiometric coefficients

equivalence point

point in a titration where the titrant completely neutralizes the analyte

exothermic

releasing energy to the environment in the form of heat; a type of exergonic process

Faraday constant

a physical constant equal to the electric charge of one mole of electrons, 96485.33 C/mol

fluorescence

luminescence released when an atom absorbs electromagnetic radiation and emits a photon when the electron falls to a lower energy state

force

a push or pull on a mass, with both magnitude and direction (vector).

frequency

number of times a point on a wave passes a reference point in one second

galvanic cell

electrochemical cell where reactions between dissimilar conductors occur through a salt bridge and electrolyte

gamma radiation

high energy ionizing photons, originating from the atomic nucleus

Gibbs free energy

a measure of the potential for reversible or maximum work done by a system at constant pressure and temperature

green chemistry

branch of chemistry concerned with lessening the environmental effect of chemicals, including development of new materials and processes

ground state

the lowest energy state of an atom, ion, molecule, or subatomic particle

half-life (t1/2)

time required to convert half of the reactant to a product or the time required for half of a radioactive isotope to decay into its daughter isotope

halogen

an element in Group VIIA of the periodic table (e.g., Br, Cl)

heat capacity

quantity of heat needed to raise the temperature of a sample by a specified amount

Henry’s Law

law that states the mass of a gas that will dissolve into solution is directly proportional to the partial pressure of the gas above the solution

Hess’s Law

law that states the energy change in an overall reaction equals the sum of the energy changes in its individual (partial) reactions

heterogeneous

consisting of dissimilar components

hydrocarbon

molecule consisting entirely of carbon and hydrogen atoms

hydrophobic

property of repelling water

hydroxyl group

functional group consisting of a hydrogen atom covalently bonded to an oxygen atom (-OH)

ideal gas constant

physical constant in the Ideal Gas Law, equal to the Boltzmann constant but with different units

indicator

substance that undergoes a visible change when its conditions change (e.g., a pH indicator)

inhibitor

substance that slows or prevents a chemical reaction

insoluble

unable to dissolve in a solvent

intermolecular force

the sum of all forces between neighboring molecules

ionic bond

chemical link between atoms caused by electrostatic force between oppositely charged ions

isolated system

thermodynamic system that can't exchange energy or matter outside of the system

IUPAC

International Union of Pure and Applied Chemistry, an authority on chemical standard

joule

SI unit of energy equal to the kinetic energy of a 1-kilogram mass moving at 1 meter per second

Kelvin temperature scale

an absolute temperature scale with 100 degrees between the freezing and boiling points of water (although values are given without degrees by convention)

kinetic energy

energy associated with motion

Law of Chemical Equilibrium

an expression of the relationship between the concentration of reactants and products of a chemical reaction mixture at equilibrium

limiting reactant

the reactant that determines how much product may result from a chemical reaction

macromolecule

molecule containing a very large number of atoms, usually more than 100