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Chemical Reactions
| Term | Definition |
|---|---|
| Chemical Reaction | A change in which 1 or more substances are converted into new substances. |
| Chemical Equation | A way to describe a Chemical Reaction using chemical formulas and other symbols. |
| Balanced Chemical Equation | has the same # of atoms of each element on both sides of the equation. |
| Chemical Reactions and Energy | there is always an energy change when a chemical reaction occurs |
| Temperature | when the temp. increases ,the rate of the reaction increases. |
| Concentration | when reactants are more concentrated , the rate of chemical reaction will increase. |
| Surface Area | when the surface area of the reactants increases, the reaction rate increases. |
| Catalyst | a catalyst lowers the amount of energy needed to start a reaction. |
| Synthesis | 2 or more substances combine to form another substance. |
| Decomposition | 1 substance breaks down, or decomposes, into 2 or more substances. |
| Endothermic Reaction | A reaction that gives off energy |
| Exothermic Reaction | A reaction that absorbs energy |
| States of Matter | Solid, liquid, gas |
| Activation Energy | What is needed to start a chemical reaction |
| Arrow -----> | you read the arrow as “yields” in a chemical equation or formula |
| 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 the products |
| Coefficient | a number placed in front of a chemical formula in an equation. Tells how many atoms or molecules of each reactant and product take part in the reaction. |
| Physical Changes | alter only the physical properties of matter; no 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 shows a chemical reaction took place |