AP Chem Masterset

Activation Energy

Minimum energy needs to be added to a system in order for the chemical reaction to occur

Alpha particle

2 protons, mass number = 4, 2+ charge Highly ionizing particle; Low energy

Anion

Negatively charge ion

Arrhenius Acid

Donates a H+ ion

Arrhenius Base

Donates a OH- ion

Atom

Smallest constituent unit of ordinary matter that has the properties of a chemical element

Atomic Mass

Average of all naturally occurring isotopes

Atomic Number

Number of protons; defines the atom

Beta Particle

-1 proton, mass number =0; medium ionizing ability, medium energy

Boiling

Phase change from a liquid to a gas

Bronsted-Lowry Acid

Donates a proton, H+

Bronsted-Lowry Base

Accepts a proton, H+

Calorimetry

Means of measuring the heat gained/ lost by a system during a chemical reaction

Catalyst

Lowers the activation energy. Not a reactant. Not a product

Cation

Positively charged ion

Chemical Equilibrium

Rate of the forward reaction equals the rate of the reverse reaction

Condensation

Phase change from a gas to a liquid

Covalent Bond

Bond formed by the sharing of electrons between atoms.

Deposition

Phase change from a gas to a solid

Dipole-Dipole

Permanent IMF present in polar molecules

Direct Relationship

Relationship between two variables where when one changes, the other changes in the same manner

Dissociate

To break into ions

Dissolve

To break into smaller pieces

Distillation

Process of separating liquids based on differences in boiling temperatures

Double Bond

Two shared pairs of electrons

Electrolyte

Dissociates into charge particles which are capable of conducting electricity

Electrolytic Cell

Redox reaction that is spontaneous

Electronegativity

The ability of an atom to attract electrons from another atom. Quantity that can’t be measured. Fluorine is most electronegative element.

Electron Affinity

Energy released when an atom gains an electron. Actual quantity that can be measured. Chlorine has the most electron affinity.

Electron

Negatively charged particle. Charge = -1, Mass ~ 0amu. Located in the orbitals surrounding the nucleus

Empirical Formula

Lowest whole number ratio of atoms in a compound

Molecular Formula

The true formula representing the actual number of each atom present in the substance.

Endothermic

Energy is gained by the system

Evaporation

Process of removing water from an aqueous solution. Solute is left behind

Exothermic

Energy is released by the system

Filtrate

Liquid that passes through the filter paper

Filtration

Process of separating a precipitate from its aqueous solution

Formula Unit

Ionically bonded atoms

Freezing

Phase change from a liquid to a solid

Galvanic / Voltaic Cell

Redox reaction that is spontaneous

Gamma Ray

0 protons, mass number = 0, Low ionizing ability, high energy

Halogen

Elements in group 17. Form halides as ions

Hydrogen Bonding

Strong dipole-dipole that results when H is bonded to F, O, or N (Special dipole that exists in only selective polar molecules)

Indirect relationship

Relationship between two variables where when one changes, the other changes in the opposite manner

Insoluble

Does not dissolve in water

Intermediate

Species produced in one step and consumed in another step

Intermolecular Forces, IMF

Attractive forces between molecules

Ion

Charge particle

Ionic Bond

Bond formed by the transfer of 1 or more electrons from the least electronegative atom to the more electronegative atom

Ionization Energy

Energy required to remove the outer electron

Kinetic Energy

Energy of motion, temperature is a measure of KE

Limiting Reactant

Reactant to runs out first thus limiting the amount of product that can be formed

London Dispersion Forces

Temporary IMF caused by the movement of electrons. Present in all nonpolar and polar substances. Most prominent in Nonpolar molecules.

Lone Pair

Unbonded electrons

Mass Number

Mass of all protons and neutrons

Melting

Phase change from a solid to a liquid

Molar Mass

grams per 1 mol

Molarity

moles of solute per liter of solution

Molecular Formula

actual number of moles of each atom in a compound

Molecule

Covalently bonded atoms

Neutron

Neutral particle. No charge. Mass = 1amu, Located in the nucleus

Noble Gas

Group 18 on the PT. Each has 8 valence electrons. Nonreactive

Orbital

Regions of probability where electrons are located. Each orbital can contain up to 2 electrons

Oxidation Number

A charge assigned to an atom that represents that charge it would have if it contained and ionic bond. Oxidation numbers are written as charge value, +4, -6, +2

Oxidation

Process of losing electrons which increases the oxidation number

Percent Error

Absolute value (Theoretical – Experimental) / Theoretical) x 100%

Percent Yield

(Quantity produced / Theoretical Amount) x 100%

Precipitate

Solid matter that forms from the reaction of two aqueous solutions

Principle Energy Level

n= 1 means first energy level. Energy levels contain sublevels

Proton

Positively charged particle. Charge = +1, Mass = 1amu, Located in the nucleus

Reduction

Process of gaining electrons which reduces the oxidation number

Significant Figures

digits that carry meaning contributing to its precision

Single Bond

One shared pair of electrons

Soluble

Dissolves in water

Solute

The species that gets dissolved to form a solution

Solution

Solute and solvent

Solvent

The species that does the dissolving to form a solution

Sources of Error

These are errors that you make in the lab which result in either increased or decreased yields.

Specific Heat

Energy required to raise 1 gram of a substance 1C

Strong Acid

Dissociates 100%

Strong Base

Dissociates 100%

Sublevel

s, p, d, and f. defines the shape

Sublimation

Phase change from a solid to a gas

Surroundings

This refers to everything outside of the system

System

This refers to the reaction

Triple Bond

Three shared pairs of electrons

Valence electrons

Outer electrons which are available for bonding

Weak Acid

Dissociate very little. Remains mostly in its molecular form

Weak Base

Dissociates very little. Remains mostly in its molecular form

theory

A set of tested hypothesis that give an overall explanation of some natural phenomenon

natural law

the same observation applies to many different systems

measurement

quantitative observation consisting of 2 parts

accuracy

refers to the agreement of a particular value with the true value

precision

refers to the degree of agreement among several elements of the same quantity

Random Error (Indeterminate Error)

measurement has an equal probability of being high or low

Systematic Error (Determinate Error)

Occurs in the same direction each time (high or low)

Unit factor

the unit that you have goes on bottom, and the unit that you want goes on top.

Density

the mass of substance per unit volume of the substance

Chemical reaction

a reaction that leads to formation of a new substance accompanied by change in color / change in properties.

Spectator ions

do not participate in the chemical reaction. That is, they are identical on both sides of the equation