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chemistry part2
| Term | Definition |
|---|---|
| Activation Energy | What is needed to start a chemical reaction. |
| arrow | you read the arrow as "yields" in a chemical equation. |
| characteristics of a chemical reaction | changes in energy or changes in properties (produce a gas (bubbles form), color change, precipitate forms or temperature) |
| 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 from of a chemical formula in an 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 and product take part in the reaction. |
| decomposition reaction | a compound breaks down into simpler substances. |
| endothermic reaction | an observable change in energy that show a chemical reaction took place; a reaction that takes heat from the solution, absorbs energy,, makes if feel cooler. |
| exothermic reaction | an observable change in energy that show a chemical reaction took place; a reaction that releases heat; gives off energy, makes if feel warmer; most chemical reactions are this type. |
| physical changes | alter only the physical properties of matter; mo new substances are formed. Can be a change in size, shape or color; change in phase (by increasing or decreasing temperature: solid, liquid, gas |
| precipitate | a solid that forms from solution during a chemical reaction; observable change that show a chemical reaction took place. |
| 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. |
| replacement reaction | one part of a compound is displaced by an element or compound from another substance (also called displacement reaction) |
| states of matter | pp. 46-50): solid liquid, and gas |
| subscripts | show the number of atoms of and element in a molecule or the ratio of elements in a compound. |
| synthesis reaction | two substances combine to form a new compound (also called composition reaction) |