AP CHEM SUMMER PREP VOCAB

accuracy

how closely a measurement aligns with a correct value

atom

smallest particle of an element that can enter into a chemical combination

Celsius (°C)

unit of temperature; water freezes at 0 °C and boils at 100 °C on this scale

chemical change

change producing a different kind of matter from the original kind of matter

chemical property

behavior that is related to the change of one kind of matter into another kind of matter

chemistry

study of the composition, properties, and interactions of matter

compound

pure substance that can be decomposed into two or more elements

cubic centimeter (cm³ or cc)

volume of a cube with an edge length of exactly 1 cm

cubic meter (m³)

SI unit of volume

density

ratio of mass to volume for a substance or object

dimensional analysis

(also, factor-label method) versatile mathematical approach that can be applied to computations ranging from simple unit conversions to more complex, multi-step calculations involving several different quantities

element

substance that is composed of a single type of atom; a substance that cannot be decomposed by a chemical change

exact number

number derived by counting or by definition

extensive property

property of a substance that depends on the amount of the substance

Fahrenheit

unit of temperature; water freezes at 32 °F and boils at 212 °F on this scale

gas

state in which matter has neither definite volume nor shape

heterogeneous mixture

combination of substances with a composition that varies from point to point

homogeneous mixture

(also, solution) combination of substances with a composition that is uniform throughout

hypothesis

tentative explanation of observations that acts as a guide for gathering and checking information

intensive property

property of a substance that is independent of the amount of the substance

kelvin (K)

SI unit of temperature; 273.15 K = 0 ºC

kilogram (kg)

standard SI unit of mass

law

statement that summarizes a vast number of experimental observations, and describes or predicts some aspect of the natural world

law of conservation of matter

when matter converts from one type to another or changes form, there is no detectable change in the total amount of matter present

length

measure of one dimension of an object

liquid

state of matter that has a definite volume but indefinite shape

liter (L)

(also, cubic decimeter) unit of volume; 1 L = 1,000 cm³

macroscopic domain

realm of everyday things that are large enough to sense directly by human sight and touch

mass

fundamental property indicating amount of matter

matter

anything that occupies space and has mass

meter (m)

standard metric and SI unit of length; 1 m = approximately 1.094 yards

microscopic domain

realm of things that are much too small to be sensed directly

milliliter (mL)

1/1,000 of a liter; equal to 1 cm³

mixture

matter that can be separated into its components by physical means

molecule

bonded collection of two or more atoms of the same or different elements

physical change

change in the state or properties of matter that does not involve a change in its chemical composition

physical property

characteristic of matter that is not associated with any change in its chemical composition

plasma

gaseous state of matter containing a large number of electrically charged atoms and/or molecules

precision

how closely a measurement matches the same measurement when repeated

pure substance

homogeneous substance that has a constant composition

rounding

procedure used to ensure that calculated results properly reflect the uncertainty in the measurements used in the calculation

scientific method

path of discovery that leads from question and observation to law or hypothesis to theory, combined with experimental verification of the hypothesis and any necessary modification of the theory

second (s)

SI unit of time

SI units (International System of Units)

standards fixed by international agreement in the International System of Units (Le Système International d’Unités)

significant figures

(also, significant digits) all of the measured digits in a determination, including the uncertain last digit

solid

state of matter that is rigid, has a definite shape, and has a fairly constant volume

symbolic domain

specialized language used to represent components of the macroscopic and microscopic domains, such as chemical symbols, chemical formulas, chemical equations, graphs, drawings, and calculations

temperature

intensive property representing the hotness or coldness of matter

theory

well-substantiated, comprehensive, testable explanation of a particular aspect of nature

uncertainty

estimate of amount by which measurement differs from true value

unit

standard of comparison for measurements

unit conversion factor

ratio of equivalent quantities expressed with different units; used to convert from one unit to a different unit

volume

amount of space occupied by an object

weight

force that gravity exerts on an object

actinide

inner transition metal in the bottom of the bottom two rows of the periodic table

alkali metal

element in group 1

alkaline earth metal

element in group 2

alpha particle (α particle)

positively charged particle consisting of two protons and two neutrons

anion

negatively charged atom or molecule (contains more electrons than protons)

atomic mass

average mass of atoms of an element, expressed in amu

atomic mass unit (amu)

(also, unified atomic mass unit, u, or Dalton, Da) unit of mass equal to 112 of the mass of a ¹²C atom

atomic number (Z)

number of protons in the nucleus of an atom

binary acid

compound that contains hydrogen and one other element, bonded in a way that imparts acidic properties to the compound (ability to release H⁺ ions when dissolved in water)

binary compound

compound containing two different elements.

cation

positively charged atom or molecule (contains fewer electrons than protons)

chalcogen

element in group 16

chemical symbol

one-, two-, or three-letter abbreviation used to represent an element or its atoms

covalent bond

attractive force between the nuclei of a molecule’s atoms and pairs of electrons between the atoms

covalent compound

(also, molecular compound) composed of molecules formed by atoms of two or more different elements

Dalton (Da)

alternative unit equivalent to the atomic mass unit

Dalton’s atomic theory

set of postulates that established the fundamental properties of atoms

electron

negatively charged, subatomic particle of relatively low mass located outside the nucleus

empirical formula

formula showing the composition of a compound given as the simplest whole-number ratio of atoms

fundamental unit of charge

(also called the elementary charge) equals the magnitude of the charge of an electron (e) with e = 1.602 × 10⁻¹⁹ C

group

vertical column of the periodic table

halogen

element in group 17

hydrate

compound containing one or more water molecules bound within its crystals

inert gas

(also, noble gas) element in group 18

inner transition metal

(also, lanthanide or actinide) element in the bottom two rows; if in the first row, also called lanthanide, or if in the second row, also called actinide

ion

electrically charged atom or molecule (contains unequal numbers of protons and electrons)

ionic bond

electrostatic forces of attraction between the oppositely charged ions of an ionic compound

ionic compound

compound composed of cations and anions combined in ratios, yielding an electrically neutral substance

isomers

compounds with the same chemical formula but different structures

isotopes

atoms that contain the same number of protons but different numbers of neutrons

lanthanide

inner transition metal in the top of the bottom two rows of the periodic table

law of constant composition

(also, law of definite proportions) all samples of a pure compound contain the same elements in the same proportions by mass

law of definite proportions

(also, law of constant composition) all samples of a pure compound contain the same elements in the same proportions by mass

law of multiple proportions

when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small whole numbers

main-group element

(also, representative element) element in groups 1, 2, and 13–18

mass number (A)

sum of the numbers of neutrons and protons in the nucleus of an atom

metal

element that is shiny, malleable, good conductor of heat and electricity

metalloid

element that conducts heat and electricity moderately well, and possesses some properties of metals and some properties of nonmetals

molecular compound

(also, covalent compound) composed of molecules formed by atoms of two or more different elements

molecular formula

formula indicating the composition of a molecule of a compound and giving the actual number of atoms of each element in a molecule of the compound.

monatomic ion

ion composed of a single atom

neutron

uncharged, subatomic particle located in the nucleus

noble gas

(also, inert gas) element in group 18

nomenclature

system of rules for naming objects of interest

nonmetal

element that appears dull, poor conductor of heat and electricity

nucleus

massive, positively charged center of an atom made up of protons and neutrons