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chemistry
| Term | Definition |
|---|---|
| kinetic molecular theory of matter | a theory that matter is composed of small particles, all in random motion. |
| physical properties | properties that can usually be observed with our senses |
| physical change | occurs when the appearance of matter changes, but composition of the matter does not change |
| physical constants | density, boiling, melting and freezing points water:0 degrees Celsius, 100 degrees Celsius, 1g/ml |
| chemical properties | a property or characteristic of a substance that is observed during a reaction in which the chemical composition or identity of the substance is changed |
| chemical change | a usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance |
| pure substances | has the same composition throughout, occurs naturally |
| elements | cannot be broken down |
| compounds | formed from the chemical combination of two or more elements |
| homogeneous mixture | the parts of the mixture are evenly distributed |
| heterogeneous mixture | the parts of the mixture are not evenly distributed |
| solutions | homogeneous mixtures that form when one substance is dissolved in another substance |
| inertia | the resistance to change |
| time interval | the time between the beginning and the end of a scientific event |
| valence | the number of electrons elements borrow or lend |
| covalent bonds | formed when atoms share electrons to fill their outer shells |
| ionic | formed when atoms transfer (gain or lose) electrons |
| mixtures | formed when two or more substances are physically combined |