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GED Physical Science
Lesson 3 Chemical Reactions
Term | Definition |
---|---|
chemical reaction | the atoms or ions of one or more substances, called the reactants, are rearranged, resulting in one or more different substances called the products |
reactants | any substance that undergoes a chemical change in a given reaction |
products | a substance obtained from another substance through chemical change |
law of conservation of mass | A principle which states that matter is neither created or destroyed during a chemical reaction, so the mass of the products always equals the mass of the reactants |
chemical equations | a symbolic representation showing the kind and amount of the starting materials and products of a reaction |
coefficient | a number or quantity placed (generally) before and multiplying another quantity, as 3 in the expression 3x |
endothermic reaction | a reaction in which the reactants absorb energy from their surroundings |
exothermic reaction | a reaction in which energy is given off with the products, usually in the form of heat or light |
activation energy | the amount of energy needed to get a reaction going |