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Chemistry
| Term | Definition |
|---|---|
| chemistry | the science of matter |
| matter | any object that has mass and occupies space |
| theory | a well established hypothesis |
| scientific law | a statement of natural phenomenon where no exceptions are known under any given circumstances |
| amorphous solids | solid without shape or form |
| gas | indefinite volume and no fixed shape |
| attractive forces | hold the particles together and give matter its appearance of continuity; strongest in solids, giving them rigidity, weaker in liquid, and weakest in gases. |
| pure substance | a definite, fixed composition and is either an element or a compound |
| homogeneous mixture | |
| heterogeneous matter | consists of two or more physically distinct phases |
| phase | a homogeneous part of a system separated from other parts by a physical boundary |
| mixture | a combination of two or more pure substances and can be homo or heterogeneous |
| scientific notation | a way to write very large or small numbers (measurements) in a compact form |
| measurement | a quantitative observation |
| metric or international system | standard system of measurements for mass lengths, time and other physical quantities |
| meter | standard unit of length of metric system |
| element | fundamental substance that cannot be broken down by chemical means into simpler substance; building blocks of matter |
| atom | smallest unit of an element that retains its properties and chemical behavior; made of subatomic particles |
| Dimitri Mendeleev | developed the periodic table in 1869 |
| metals | solids at room temperature (except mercury); shiny, good conductors of heat and electricity; malleable (can be shaped); ductile; have a high melting point and density |
| nonmetals | not shiny; have fairly low melting points and densities; poor conductors of heat and electricity; can combine with each other to form molecullar compounds |
| metalloids | have properties between metals and nonmetals |
| compound | a substance containing two or more elements that are chemically combined in a definite proportion; decompose chemically into simpler |