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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 |