Term | Definition |
chemistry | is the study of the properties of matter and how matter changes |
element | is a substance that cannot be broken down into any other substance by chemical or physical means |
compound | is a substance made of two or more elements chemically combined in a specific ration, or proportion |
mixture | is made from two or more pure substance-elements,compounds,or both-that are in the same place but not combined as a new material |
solution | is a well-mixed mixture |
physical change | a change that alters the form or appearance of a material but does not make the material into another substance |
chemical change | a change in matter that produces new substances |
precipitate | a solid that forms from solution during a chemical reaction |
atom | the smallest particle of an element |
moleclue | the combination of two or more atoms |
chemical bond | the force that holds atoms together |
chemical equation | is a shorter,easier way to show chemical reactions, using symbols instead of words |
symbol | most elements are represented by a one-letter or two-letter symbol |
chemical formula | a compound is represented by a "word" called a chemical formula which shows the ratio of elements |
subscript | show the number of atoms of an element in a molecule |
reactants | the materials you have at the beginning of a chemical reaction |
products | when the reaction is complete, you have different materials |
conservation of matter | the principle stating that matter is not created or destroyed during a chemical reaction |
coefficient | is a number in front of a chemical formula in the equation |
synthesis | when two or more substances (elements or compounds) combine to make a more complex substance |
decomposition | reaction breaks down compounds into simpler products |
replacement reaction | a reaction in which one element replaces another in a compound or in which two elements in different compounds trade places |
exothermic reaction | a reaction that releases energy in the from of heat |
endothermic reacton | A reaction that absorbs energy |
activation energy | is the minimum amount of energy that has to be added to start a reaction |
concentration | is the amount of one material in a given volume of another material |
catalyst | is a material that increases the rate of a reaction by lowering the activation energy |
enzymes | provide a surface on which reactions take place |
inhibitor | a material used to decrease the rate of a reaction |
combustion | is a rapid reaction between oxygen and a substance called fuel |
fuel | is a material that releases energy when it burns |