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CHEMISTRY VOCABULARY first semester |
| Chemistry: | The study of matter and its changes. |
| Matter: | Anything that has mass and occupies space. |
| Accuracy: | Closeness of a measurement to the true value. |
| Precision: | Closeness of repeated measurements to one another. |
| Chemical change: | Change in which a pure substance breaks down or a new one is made. |
| Physical change: | Change in which no pure substance appears or disappears. |
| Solid: | State in which matter has definite shape and volume. |
| Liquid: | State in which matter has definite volume but no defined shape. |
| Gas: | State in which matter has no definite shape or definite volume. |
| Element: | Pure substance that cannot be broken down into anything simpler
by ordinary means (i.e., without a nuclear reaction). |
| Compound: | Combination of two or more elements in definite proportions. |
| Mixture: | Combination of elements or compounds in indefinite proportions. |
| Atom: | Smallest particle of an element that still has properties of that element. |
| Molecule: | Smallest particle of a compound that still has properties of that compound. |
| Proton: | Subatomic particle with mass of 1 and a positive charge. |
| Neutron: | Subatomic particle with mass of 1 and no charge (neutral). |
| Electron: | Subatomic particle with very little mass and a negative charge. |
| Atomic number: | The number of protons in an atom. |
| Atomic "weight" = mass number: | Sum of the number of protons and neutrons. |
| Isotope | A variant form of an atom, differing in atomic weight from other forms. |
| Ion: | An electrically charged atom or combination of atoms. |
| Ionic bond: | Chemical bond formed by electrical attraction between + and - ions. |
| Covalent bond: | Chemical bond formed by the sharing of electrons between atoms. |
| Energy: | The capacity to do work (measured in Joules). |
| Reactant: | A starting material, or anything on the left of a chemical reaction. |
| Product: | Any substance produced on the right side of a chemical reaction. |
| Empirical formula: | The simplest formula with a particular percentage composition. |
| Precipitation: | Formation of an insoluble product in a reaction. |
| Oxidation: | Loss of electrons, or an increase in the oxidation number. |
| Reduction: | Gain of electrons, or a reduction in the oxidation number. |
| Acid: | Any substance that can has (and can give away) hydrogen ions. |
| Base: | Any hydroxide or other substance that can combine with H+ ions. |
| Joule: | The SI (metric) unit of energy, equal to one Newton-meter. |
| Calorie: | The heat energy required to raise 1 g of water by 1 degree C. |