Term | Definition |
Element | Substance that cannot be broken down into any other substances by chemical or physical means. |
Compound | A substance made of two or more element chemically combined in a specific ratio, or proportion. |
Mixture | Is made up of two or more pure substances-elements, compounds, or both- that are in the same place but not combined as a new material. |
Solution | A well-mixed mixture. |
Physical Change | A change that alters the form or appearance of a material but does not make the material into material into another substance. |
Chemical Change | A change in matter that produces new substances. Example: substances --> made + steps. |
Precipitate | A solid that forms from solution during a chemical reaction. |
Atom | The smallest particle of an element/ |
Molecule | The combination of two or more atoms. |
Chemical Bond | The force that holds atoms together. |
Chemical Equation | A shorter, easier way to show chemical reactions, using symbols instead of words. |
Symbol | Most elements are represented by a one word letter or two letter symbol. |
Chemical Formula | A compound is represented by a "word" called a chemical reactions, using symbols instead of words. |
Subscript | Shows 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, called the products of the reaction. |
Coefficient | 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 in trade places. |
Exothermic Reaction | A reaction that releases energy in the form of heat. |
Endothermic Reaction | A reaction that absorbs energy. |
Activation Energy | The minimum amount of energy that has to be added to start a reaction. |
Concentration | The amount of one material in a given volume of another material. |
Catalyst | A material that increases the rate of a reaction by lowering the activation energy. |
Enzymes | Provides a surface on which reactions takes place. |
Combustion | A rapid reaction between oxygen and a substance called a fuel. |
Fuel | A material that releases energy when it burns. |