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Chemical Reactions
Chemical Reactions Vocabulary
| Term | Definition |
|---|---|
| physical change | a change that alters the form or appearance of a substance but does not change it into another substance |
| chemical change | a change in which one or more substances combine or break apart to form new substances |
| physical property | a characteristic of a substance that can be observed without changing the substance into another substance |
| chemical property | a characteristic of a substance that describes its ability to change into other substances |
| reactant | a substance that enters into a chemical reaction |
| product | a substance formed as a result of a chemical reaction |
| endothermic reaction | a reaction that absorbs energy - the temperature surrounding the reaction decreases |
| exothermic reaction | a reaction that releases energy - the temperature surrounding the reaction increases |
| precipitate | a solid that forms from a solution during a chemical reaction |
| subscript | a number in a chemical formula that tells the number of atoms in a molecule or the ration of elements in a compound |
| coefficient | a number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction |
| chemical equation | a short, easy way to show a chemical reaction, using symbols |
| law of conservation of mass | the principle that the total amount of matter is neither created nor destroyed during any chemical or physical change |
| open system | a system in which matter can enter from or escape to the surroundings |
| closed system | a system in which no matter is allowed to enter or leave |
| synthesis reaction | a chemical reaction in which two or more simple substances combine to form a new, more complex substance |
| decomposition reaction | a chemical reaction that breaks down compounds into simpler products |
| replacement reaction | a reaction in which one element replaces another in a compound or when two elements in different compounds trade places |
| combustion reaction | a reaction in which water and carbon dioxide are the products |
| evidence of a chemical change | color change, formation of a gas, temperature change, and the formation of a precipitate |