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Chem Part 2 +0+
Chemistry definitions! Study them!
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 Change | 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 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 must equal the total mass of the products |
Controlling rates of Reaction | Concentration Temperature Surface Area Catalysts Enzymes Inhibitors |
Decomposition Reaction | A compound breaks down into simpler 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; a reaction that releases heat; gives off energy, makes it feel warmer; most chemical reactions are this type. |
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 |
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 | Solid, liquid, and gas |
Subscripts | Show the number of atoms of an 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) |