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Chemical Reactions. Section 6.2. I. Reactants and Products. Chemical reaction Process where atoms or groups of atoms in substances are reorganized Production of… Heat or light, and formation of a gas, liquid, or solid Chemical rxn physical rxn chemical rxn.
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Chemical Reactions Section 6.2
I. Reactants and Products • Chemical reaction • Process where atoms or groups of atoms in substances are reorganized • Production of… • Heat or light, and formation of a gas, liquid, or solid Chemical rxn physical rxn chemical rxn
II. Endothermic and Exothermic reactions • Endothermic reaction • Endo= internal or absorbing • Thermic= relating to heat • Definition: Absorption of energy in the form of heat • Exothermic reaction • Exo= external or outside • Thermic: relating to heat • Definition: releases energy in the form of heat
III. Chemical Equations • Chemical Formulas • Describes substances in the reaction • Arrows indicate the process of change • Reactants • Starting substances; on left side of the arrow • Products • Substances formed during the reaction; on the right side of the arrow
III. Chemical Equations cont. • Example: • Glucose and oxygen react to form carbon dioxide and water • Example of balanced equation: • Mass cannot be created or destroyed; just changed form
Bombardier Beetle http://www.youtube.com/watch?v=_352pC1FXBA
Water and Solutions Section 6.3
I. pH and Buffers • The measure of concentration of H+ in a solution is called pH • Acidic solutions have pH values lower than 7 • Basic (alkaline) solutions have pH values higher than 7
II. Buffers • Mixtures that can react with acids or bases • Keep the pH within a particular range • Cellular pH with buffer: 6.5-7.5 range
III. Energy of Reactions • Activation energy • Minimum amount of energy needed for reactants to form products in a chemical reaction
IV. Types of Chemical Reactions • Exothermic Reactions • Energy released in the form of heat • Energy of the product is lower than energy of the reactants
IV. Types of Chemical reactions cont. B. Endothermic • Energy absorbed in form of heat • Energy of the products is higher than energy of the reactants
I. Enzymes • Catalyst: • Substance that lowers the activation energy needed to start a chemical reaction • Does not increase amount of product made • Does not get used up in the reaction • Enzymes are biological catalysts • Made of proteins
I. Enzymes cont. • Reactants that bind to the enzyme are called substrates • Active site • Specific location where a substrate binds on an enzyme • Changes shape and forms enzyme-substrate complex • Helps chemical bonds in the reactants to be broken and new bonds to form • Factors such as pH, temperature, and other substances affect enzyme activity • Naming • Substrate name • Ending in -ase