Summary of lessons so far
- Summary of lessons so far
- Glossary of Words
Chemistry in Context
Chemistry deals with the composition, structure, and properties of matter, and the ways by which various forms of matter may be interconverted. Thus, it occupies a central place in the study and practice of science and technology.
Chemists use the scientific method to perform experiments, pose hypotheses, and formulate laws and develop theories, so that they can better understand the behavior of the natural world. To do so, they operate in the macroscopic, microscopic, and symbolic domains. Chemists measure, analyze, purify, and synthesize a wide variety of substances that are important to our lives.
Phases and Classification of Matter
Matter is anything that occupies space and has mass. The basic building block of matter is the atom, the smallest unit of an element that can enter into combinations with atoms of the same or other elements. In many substances, atoms are combined into molecules.
On earth, matter commonly exists in three states: solids, of fixed shape and volume; liquids, of variable shape but fixed volume; and gases, of variable shape and volume. Under high-temperature conditions, matter also can exist as a plasma.
Most matter is a mixture: It is composed of two or more types of matter that can be present in varying amounts and can be separated by physical means. Heterogeneous mixtures vary in composition from point to point; homogeneous mixtures have the same composition from point to point.
Pure substances consist of only one type of matter. A pure substance can be an element, which consists of only one type of atom and cannot be broken down by a chemical change, or a compound, which consists of two or more types of atoms.
Glossary of Words
smallest particle of an element that can enter into a chemical combination
study of the composition, properties, and interactions of matter
pure substance that can be decomposed into two or more elements
substance that is composed of a single type of atom; a substance that cannot be decomposed by a chemical change
state in which matter has neither definite volume nor shape
combination of substances with a composition that varies from point to point
(also, solution) combination of substances with a composition that is uniform throughout
tentative explanation of observations that acts as a guide for gathering and checking information
state of matter that has a definite volume but indefinite shape
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
realm of everyday things that are large enough to sense directly by human sight and touch
fundamental property indicating amount of matter
anything that occupies space and has mass
realm of things that are much too small to be sensed directly
matter that can be separated into its components by physical means
bonded collection of two or more atoms of the same or different elements
gaseous state of matter containing a large number of electrically charged atoms and/or molecules
homogeneous substance that has a constant composition
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
state of matter that is rigid, has a definite shape, and has a fairly constant volume
specialized language used to represent components of the macroscopic and microscopic domains, such as chemical symbols, chemical formulas, chemical equations, graphs, drawings, and calculations
well-substantiated, comprehensive, testable explanation of a particular aspect of nature
force that gravity exerts on an object