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Chemical Reactions
Term | Definition |
---|---|
arrow | read as yields in a chemical formula |
characteristics of a chemical reaction | changes in energy or properties |
proof of chemical reaction | gas produced (bubbles); light produced; temperature change; color change; precipitate forms; odor; new substance |
chemical equations | shorter, easier way to show chemical reactions by using symbols instead of words |
coefficient | number placed in front of a chemical formula in an equation. Tells how many molecules of each reactant and product take part in the reaction |
conservation of mass | the amount of matter involved in a chemical reaction does not change. The total mass of the reactants must equal the total moss of the products |
physical changes | alter only the physical properties of matter; no new substances formed |
chemical changes | alter the chemical properties of matter; new substances with new properties are formed |
precipitate | a solid that forms from a liquid during a chemical reaction |
products | the materials you have after a chemical reaction; written on the right side of the formula |
reactants | the materials you have at the beginning of a chemical reaction; written on the left side of the formula |
states of matter | solid, liquid or gas |
subscripts | show the number of atoms of an element in a molecule |
valence electrons | The electrons in the outermost energy level of an atom |
compound | A substance made of two or more elements that are chemically bonded |
Gas production | bubbles, fizzing, smoke |