Chemical Reactions

Section 6.2

I. Reactants and Products

A. Chemical reaction1. Process where atoms or groups of atoms

in substances are reorganized2. Production of…

i. Heat or light, and formation of a gas, liquid, or solid

Chemical rxn physical rxnchemical rxn

II. Endothermic and Exothermic

reactionsA. Endothermic reaction 1. Endo= internal or absorbing2. Thermic= relating to heat3. Definition: Absorption of energy in the form of

heat

B. Exothermic reaction1. Exo= external or outside2. Thermic: relating to heat3. Definition: releases energy in the form of heat

III. Chemical Equations

A. Chemical Formulas1. Describes substances in the reaction2. Arrows indicate the process of change

B. Reactants1. Starting substances; on left side of the

arrow

C. Products1. Substances formed during the reaction; on

the right side of the arrow

III. Chemical Equations cont.

A. Example:1. Glucose and oxygen react to form carbon

dioxide and water

B. Example of balanced equation:1. 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 BuffersA. The measure of concentration of H+ in a solution

is called pH

B. Acidic solutions have pH values lower than 7

C. Basic (alkaline) solutions have pH values higher than 7

II. BuffersA. Mixtures that can react with acids or

bases

B. Keep the pH within a particular range1. Cellular pH with buffer: 6.5-7.5 range

III. Energy of Reactions

A. Activation energy1. Minimum amount of energy needed for reactants to form products in achemical reaction

IV. Types of Chemical ReactionsA. Exothermic Reactions

1. Energy released in the form of heat2. Energy of the product islower than energy of thereactants

IV. Types of Chemical

reactions cont.B. Endothermic1. Energy absorbed in form of heat2. Energy of the products is higher than energy

of the reactants

Enzymes

I. EnzymesA. Catalyst:

1. Substance that lowers the activation energy needed to start a chemical reaction

2. Does not increase amount of product made3. Does not get used up in the reaction

B. Enzymes are biological catalysts

C. Made of proteins

I. Enzymes cont.A. Reactants that bind to the enzyme are called

substrates

B. Active site1. Specific location where a substrate binds on an

enzyme2. Changes shape and forms enzyme-substrate

complexi. Helps chemical bonds in the reactants to be

broken and new bonds to form

C. Factors such as pH, temperature, and other substances affect enzyme activity

D. Naming1. Substrate name2. Ending in -ase