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 (produced 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 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 |
Concentration | (amount of one material in a given amount of another material) |
Temperature | (higher heat causes faster reactions) |
Surface Area | (increased surface area = increased reaction) |
Catalysts | (materials that increases the rate of reaction) |
Enzymes | (biological catalysts) |
Inhibitors | (decreases the rate of a reaction) |
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 | (pp. 46-50): 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) |