Gen Chem 1 - Chapter 1 Vocab

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

Hypothesis

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

Theory

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

Law

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

Macroscopic Domain

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

Microscopic Domain

realm of things that are too small to be sensed directly

Symbolic Domain

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

Matter

anything that occupies space and has mass

Solid

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

Liquid

state of matter that has a definite volume but indefinite shape

Gas

state in which matter has neither definite volume nor shape

Plasma

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

Weight

force that gravity exerts on an object

Mass

fundamental property indicating amount of matter

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

Pure substance

homogeneous substance that has a constant composition

Elements

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

Compound

purse substance that can be decomposed into two or more elements

Mixture

matter that can be separated into its components by physical means

Homogenous mixture

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

Heterogenous mixture

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

Solution

a homogeneous mixture

Atom

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

Molecule

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

Physical State

describes the form a substance takes, such as solid, liquid, or gas, which is determined by the arrangement and movement of its particles

Phase

a region of space in which all the physical properties of a material are essentially uniform, defined by the arrangement and behavior of its constituent particles

Physical change

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

Distillation

the action of purifying a liquid through heating or cooling

Physical Property

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

Extensive Property

property of a substance that depends on the amount of substance

Intensive Property

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

Melting Point

the temperature at which a substance transitions from solid to a liquid state, occurring at a constant temperature and pressure.

Boiling Point

the temperature at which a substance transitions from a liquid state to a gas state, occurring at a constant temperature and pressure.

Chemical Property

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

Chemical change

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

Units

standard of comparison of measurements

SI Base units

standards fixed by international agreement in the International System of Units

SI prefixes

used to form decimal multiples and submultiples of SI units (like meters, grams, or seconds)

Common Unit Prefixes

standardized symbols added to a base unit of measurement to denote a multiple or fraction of that unit

Derives units

a unit of measurement that is formed by combining base units through algebraic multiplication or division, without the introduction of numerical factors.

Density

ratio of mass to volume for a substance or object

Exact number

number derived by counting or by definition

Accuracy

how closely a measurement aligns with a correct value

Uncertainty

estimate of amount by which measurement differs from true value

Precision

how closely a measurement matches the same measurement when repeated

Significant figures

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

Conversion factors

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

Dimensional analysis

versatile mathematical approach that can be applied to computations ranging from simple unit conversions to more complex, multistep calculations involving several different qualities

Equalities

used to create conversion factors

Temperature Scales

intensive property of matter that is a quantitative measure of "hotness" and "coldness"

Degrees Fahrenheit

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

Degrees Celsius

unit of temperature; water freezes at 0C and boils at 100C

Kelvins

unit of temperature; water freezes at 273K and boils at 373K.