chemical reactions
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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
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