Ch 1 Definitions and Equations

chemistry

study of the composition, properties, and interactions of matter

matter

anything that occupies space and has mass

theory

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

experiment

a highly controlled procedure designed to generate observations that may support a hypothesis or prove it wrong

law

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

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

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

physical property

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

chemical property

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

physical change

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

chemical change

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

element

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

compound

pure substance that can be decomposed into two or more elements

atom

Smallest particle of an element that maintains the characteristics of the element

measurement

a quantity that has both a number and a unit

significant figure (digits)

all of the measured digits in a determination, including the uncertain last digit

precision

how closely a measurement matches the same measurement when repeated

accuracy

how closely a measurement aligns with a correct value

heterogeneous mixture

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

homogeneous mixture

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

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 much too small to be sensed directly

mass

fundamental property indicating amount of matter

matter

anything that occupies space and has mass

mixture

matter that can be separated into its components by physical means

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

density equation

D = mass/volume = g/mL or g/cm³

degrees Celsius and Kelvin equation

T in K = T in ⁰C + 273.15