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Chapter 2
Book L
Chemical Reactions
Name ___________Teachers’ Copy______
Class __________________________________
Test Date _______________________________
Chapter 2 –Chemical Reactions Outline
Section 1-Forming New Substances P. 28 - 31
I.
Chemical Reactions
*Notes-A ______Chemical Reaction____ is a process in which one or more substances
change to make one or more new substances. Milk souring, food being digested, and a
match burning are all examples of chemical changes.
A. Signs of Chemical Reactions
List 4 signs of chemical reactions.
_____Change of color_
___Gas formation__
____Energy change____
____Solid formation__
B. A Change of Properties
NaCl = table salt
II. Bonds: Holding Molecules Together
A. Breaking and Making Bonds
*Notes-For a chemical bond to break, ___Energy_____ is required.
B. New Bonds, New Substances
*Notes-A chlorine gas molecule is a ____diatomic___________ molecule. A
chlorine molecule is made up of ___2_____ atoms of chlorine.
Cl2
Chapter 2 –Chemical Reactions Outline
Section 2-Chemical Formulas and Equations p. 32 - 37
I.
Chemical Formulas
A ______Chemical Formula______ is a shorthand way to use chemical symbols and
numbers to represent a substance.
*Notes-A ______Subscript_________ is a number written below and to the right of a
chemical symbol. C6H12O6 The 6, 12, and 6 are all subscripts.
*To find the number of atoms in a compound you should __add____ the subscripts.
*Notes-If there is no subscript, only __1_____ atom of that element is present.
*In ZnCl2 there are __3_____ atoms because 1+2 = 3.
A. Writing Formulas for Covalent Compounds
*Notes-the prefix di means ___2_______ atoms in a compound.
*Notes-the prefix tri means ___3_______ atoms in a compound.
*Notes-dinitrogen trioxide would have ___2_ atoms of nitrogen and ___3___
atoms of oxygen.
N2O3
B. Writing Formulas for Ionic Compounds
II. Chemical Equations
A. Describing Reactions by Using Equations
B. From Reactants to Products
*Notes-A substance or molecule that participates in a reaction is called a
____Reactant_________.
*Notes-The substance that forms in a chemical reaction is called a
_____Product__________. You produce a product in a chemical reaction.
C. The Importance of Accuracy
D. The Reason Equations Must be Balanced
*Notes-The Law of Conservation of Mass dictates that chemical equations must be
balanced because atoms are never _____lost__or _____gained__in a chemical
reaction.
E. How to Balance an Equation
*Coefficient
2H2 + O2
*Reactants
2H2O
*Subscript *Yield Sign
*Product
*Note-The ____coefficient________ is the number that is placed in front of a chemical
symbol or formula.
** You can change the coefficient, but NOT the subscript #.
Chapter 2 –Chemical Reactions Outline
Section 3-Types of Chemical Reactions p. 38 - 41
I.
Synthesis Reactions
*Notes- In a _______Synthesis Reaction_____ two or more substances combine to
form one new substance.
*__2Na_____ + _Cl2____
_____2NaCl_______ (SALT)
Sodium reacts with chlorine to form sodium chloride
II.
Decomposition Reactions
*Notes-In a ____Decomposition Reaction___ a single compound breaks down to
form two or more compounds.
*____H2CO3__________
__H2O________ + ____CO2_____ (SODA)
Carbonic acid decomposes to form water and carbon dioxide
III.
Single-Displacement Reactions
*Notes-In a _Single Displacement Reaction_ an element replaces another element
that is a part of a compound.
*___Zn______ + ___2HCl_____
____ZnCl2____ + ____H2_______
Zinc replaces the hydrogen in hydrochloric acid to form zinc chloride and hydrogen
a. Reactivity of Elements
IV.
Double-Displacement Reactions
Sodium chloride + silver fluoride
NaCl
+AgF
sodium fluoride + silver chloride
NaF
+ AgCl
Chapter 2 –Chemical Reactions Outline
Section 4-Energy and Rates of Chemical Reactions p. 42 - 47
I.
Reactions and Energy
a. Exothermic Reactions
*Note-Exothermic Reactions give off_______Energy_____________.EXIT-thermic
(energy released)
b. Endothermic Reactions
*Note-Endothermic Reactions “take in” energy.
AND-othermic (energy absorbed)
c. The Law of Conservation of Energy
II.
They need __Energy_____ to get started.
Rates of Reactions
a. Activation Energy
b. Sources of Activation Energy
Exothermic Reaction
Endothermic Reaction
activation
energy!
*Notes-Complete these graphs with the information from page 45 in your book. Know them for the test!
III.
Factors Affecting Rates of Reactions
a. Temperature
b. Concentration
c. Surface Area
*Notes-Grinding a powder can increase the rate of a ____Reaction_________.
d. Inhibitors
e. Catalysts
*Notes-A ___Catalyst_________ lowers the activation energy of a reaction, which
allows the reaction to happen more quickly.