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Chemistry pt.2
Term | Definition |
---|---|
Activation Energy | what is needed to start a chemical reaction |
Arrow | you read the arrow as "yields" in a chemical equation or formula |
Characteristics of a Chemical Reaction | changes in energy or changes in properties (produce a gas(bubbles form), color change, precipitate forms, or temperature change.) |
chemical changes | alter the chemical properties of matter; new substances with new properties are formed. |
chemical equations | a shorter, easier way to show chemical reactions by using symbols instead of words |
coefficient | a number placed in front of a chemical formula in a equation. Tells how many atoms or 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 mass of products |
controlling rates of a reaction | concentration, temperature, surface area, catalysts, enzymes, and inhibitors |
decomposition reaction | a compound breaks down into smaller substances. |
endothermic reaction | an observable change in energy that shows a chemical reaction took place; a reaction that takes heat from the solution, absorbs energy, makes it feel cooler |
exothermic reaction | an observable change in energy that shows a chemical reaction took place; gives off energy and makes it feel warmer, most chemical reactions are this type |
physical changes | alter only the physical properties of matter; no new substances are formed, change in size, shape or color. |
percipitate | a solid that forms from a solution during a chemical reaction; |
products | the materials you have after a chemical reaction; writtin 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 |
replacement reaction | one part of a compound id displaced by an element or a compound from another substance |
subscripts | show the number of atoms in an element in a molecule or the ratio of element in a compound |
synthesis reaction | two substances combine to form a new compound (also called a composition reaction) |