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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 |