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Physical Science Ch 5

a solid that forms from a solution during a chemical reaction
endothermic reaction
A reaction that absorbs energy in the form of heat
exothermic reaction
a reaction that releases energy in the form of heat
chemical equation
a short, easy way to show a chemical reaction, using symbols instead of words
a number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound
a substance that enters into a chemical reaction
A substance formed as a result of a chemical reaction.
conservation of mass
the principle stating that matter is not created or destroyed during a chemical reaction
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
a chemical reaction in which two or more simple substances combine to form a new, more complex substance
a chemical reaction that 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.
activation energy
the minimum amount of energy needed to start a chemical reaction
the amount of one material dissolved in a given amount of another material
a material that increases the rate of a reaction by lowering the activation energy
a biological catalyst that lowers the activation energy of reactions in cells
a material used to decrease the rate of a reaction
a rapid reaction between oxygen and fuel that produces thermal energy
A material that releases energy when it burns