AP Chemistry Unit 1, 2, and 3

Chemistry

the study of properties of materials and changes that they undergo

Matter

the physical material of the universe
has mass
occupies space

Property

any characteristic that allows us to recognize a particular type of matter and to distinguish it from other types

Elements

made up of unique atoms, cannot be decomposed into simpler substances

atoms

Building blocks of matter

Molecules

combinations of two or more atoms

hypothesis

A testable prediction, often implied by a theory

scientific law

concise statement or equation that summarizes tested hypotheses

theory

an explanation using an integrated set of principles that organizes observations and predicts behaviors or events

States of matter

the physical forms of matter, which include solid, liquid, and gas

Composition

the makeup of something (element, compound, mixture)

Gas

have no fixed volume or shape, conforms to the shape of container, compressible

Liquid

Volume is independent of container, no fixed shape, incompressible

Solid

have a volume and shape that is independent of the container; rigid, incompressible

Oxygen, nitrogen, fluorine, bromine, iodine, chlorine, hydrogen

diatomic elements

Compounds

2 or more elements chemically combined

Law of Constant Proportions

law that states that, in chemical compounds, the ratio of the elements is always the same

Mixtures

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

solution

A homogeneous mixture of two or more substances

physical property

a characteristic that can be observed or measured without changing the identity of the substance (color, density, odor, melting point, etc)

chemical property

a property of matter that describes a substance's ability to participate in chemical reactions

intensive property

a property that depends on the type of matter in a sample, not the amount of matter (temperature, melting point)

extensive property

a property that depends on the amount of matter in a sample (mass, volume, etc.)

physical change

A change in a substance that does not involve a change in the identity of the substance (changes of state, like melting, freezing, evaporating, sublimation, and deposition)

chemical change

A change that occurs when one or more substances change into entirely new substances with different properties.

metric system

The decimal measuring system based on the meter, liter, and gram as units of length, capacity, and weight or mass.

Systeme International (SI)

A common metric system of units of measurement used by scientists.

Meter

SI unit of length

Kilogram

SI unit for mass

Mass

A measure of the amount of matter in an object

Temperature

A measure of how hot or cold something is.

Celsius scale

water freezes at 0 and boils at 100

Kelvin scale

SI unit for temperature, water freezes at 273.15 K and boils at 373.15 K (at sea level)

Volume

(units of length)^3

no

Is the liter an SI unit?

density

mass/volume

exact numbers

Numbers that have no uncertainty and thus do not limit the number of significant figures in any calculation.

inexact numbers

those numbers whose values have some uncertainty; obtained by measurement

precision

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

Accuracy

A description of how close a measurement is to the true value of the quantity measured.

The Atomic Theory of Matter

the idea that matter is made up of fundamental particles called atoms

Democritus

Greek philosopher that said all matter is made of tiny particles called "atomos" or atoms

Law of Conservation of Mass

the law that states that mass cannot be created or destroyed in ordinary chemical and physical changes

conservation

the principle that properties such as mass remain the same despite changes in the forms of objects

Law of Multiple Proportions

if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers

Subatomic particles

Particles found within the atom, mainly protons, neutrons, and electrons.

Cathode rays

streams of electrons that are produced when a high voltage is applied to electrodes in an evacuated tube

-1.76*10^8 C/g

charge to mass ratio of electron

Coulomb

SI unit of charge

Radioactivity

The process in which some substances spontaneously emit radiation

beta radiation

Radiation that is made up of beta particles; is deflected toward a positively charged plate when radiation from a radioactive source is directed between two electrically charged plates. Of negative charge and low mass

gamma radiation

High-energy radiation emitted by the nuclei of radioactive atoms. Neutral charge

alpha radiation

Radiation that is made up of alpha particles; is deflected toward a negatively charged plate when radiation from a radioactive source is directed between two electrically charged plates. High mass, positively charged

protons

Positively charged particles

neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

electron

A subatomic particle that has a negative charge

Atomic mass unit

a unit of mass that describes the mass of an atom or molecule

Angstrom

A unit of length equal to one ten-thousandth 10-10 of a meter.

atomic number (Z)

the number of protons in the nucleus of an atom

mass number (A)

the total number of protons and neutrons in the nucleus of an atom

isotopes

Atoms of the same element that have different numbers of neutrons

nuclide

a general term for a specific isotope of an element

Atomic weight

Average of the mass numbers of all isotopes

Mass spectrometer

an instrument used to determine the relative masses of atoms by the deflection of their ions on a magnetic field

Periods

Horizontal rows on the periodic table

groups/families

Vertical columns on the periodic table

Metals

malleable, ductile, lustrous, good thermal and electrical conductors

Nonmetals

brittle as solids, dull in appearance, bad conductors of heat and electricity

Metalloids

Elements that have properties of both metals and nonmetals.

Formula unit

the lowest whole-number ratio of ions in an ionic compound

Molecular compounds

compounds composed of molecules

Molecular formula

A chemical formula that shows the number and kinds of atoms in a molecule, but not the arrangement of the atoms.

empirical formula

a chemical formula showing the ratio of elements in a compound rather than the total number of atoms

Structural formula

a formula that shows the arrangement of atoms in the molecule of a compound.

Ion

A charged atom

Cation

A positively charged ion

Anion

A negatively charged ion

polyatomic ion

A charged group of covalently bonded atoms

ionic compound

A compound that consists of positive and negative ions

Chemical nomenclature

the rules used in naming substances

monoatomic ion

an ion formed from a single atom

oxyanions

polyatomic ions that contain oxygen

Stoichiometry

the quantitative relationship between reactants and products in a chemical reaction

chemical equation

a way to describe a chemical reaction using chemical formulas and other symbols

reactants

A starting material in a chemical reaction

products

The elements or compounds produced by a chemical reaction.

Combination reaction

a chemical change in which two or more substances react to form a single new substance (more reactants than products)

decomposition reaction

a reaction in which a single compound breaks down to form two or more simpler substances (more products than reactants)

Combustion reactions

a substance combines with oxygen, releasing a large amount of energy in the form of light and heat. Rapid reactions that produce a flame

mole

the SI base unit used to measure the amount of a substance

Avogadro's number

6.02 x 10^23

molar mass

the mass of one mole of a pure substance

limiting reactants/ limiting reagents

one or more reactants that are completely consumed

theoretical yield

the maximum amount of product that can be produced from a given amount of reactant

actual yield

the measured amount of a product obtained from a reaction

percent yield

actual yield/theoretical yield x 100

Solvent

the substance present in the greatest quantity, does the dissolving

Solute

A substance that is dissolved in a solution.

Electrolyte

a substance whose aqueous solutions contain ions

nonelectrolyte

a substance that does not form ions in solution