Chemistry Chapter 2: Section 2.1

anything that occupies space and has mass 

Matter

out of nothing

Ex nihilo

the effect of temperature on the state of matter (energy of motion)

Kinetic energy

an indirect measurement of the particles’ average kinetic energy 

Temperature

state of matter that is characterized by a definite shape and volume 

Solid

state of matter characterized by a definite volume but no definite shape

Liquid

a state of matter that has no definite shape or volume and is easily compressed

Gas

state of matter that is a hot gas in which atoms are partially broken down to form charged particles; probably the most common state of matter in the universe

Plasma

a form of matter with unique properties that make it different from every other substance

Substance

any of the smallest particles into which an element can be divided and still remain that element

Atoms

substances that cannot be broken down into simpler substances by ordinary chemical means

Elements

unique symbols assigned to an element

Atomic symbol

group of two or more atoms that are linked by chemical bonds to form distinct units

Molecules

grouping of symbols that tells what types of atoms compose the compound and the number of each type of atoms in one molecule of the compound

Formula

“same”, “kind”; composed of the same kind of matter throughout a sample

Homogeneous

a substance consisting of two or more pure substances that are physically mixed but not chemically combined 

Mixture

two or more elements bonded together; substance that can be decomposed by chemical means into simpler substances

Compound

most abundant element in the atmosphere

Oxygen

most abundant element in the crust of the earth

Iron

most abundant element in the universe as a whole 

Hydrogen

substances that have a definite composition and are homogenous; an element or compound 

Pure substances

mixture that consists of pure substances that are incompletely mixed

Heterogeneous

homogeneous part of a system that is in contact with but physically distinct from other parts of the system 

Phase

• proposed by John Dalton

1. Every element consists of tiny, indivisible, indestructible particles called atoms 

2. All of the atoms of a particular element have the same size, mass, and chemical behavior 

3. Differences in properties of elements result from differences in the atoms of the elements 

4. The atoms of the elements in a compound are combined in a definite ratio

5. A chemical reaction is the result of a rearrangement, combination or separation of atoms 

Atomic theory

the result of a rearrangement, combination or separation of atoms 

chemical reaction

law stating that the masses of each element in a given compound always have the same ratio

Law of definite composition

law stating that when two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other element are in a ratio of small whole numbers

Law of the multiple proportions