Unit 5: Chemical Bonds and Reactions 2015 1
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Unit 5: Chemical Bonds & Reactions Notes Packet
VOCABULARY:
Term
Chemical Bonds
Valence Electron
Definition
Electron in the outermost shell of an atom
that determines the atoms chemical
properties
Ionic Bond
Covalent Bond
Metallic Bond
A bond formed by the attraction between
positively charged metal ions and the
electrons around them
Molecule
Compound
Substance made up of atoms of two or more
different elements joined by chemical bonds
Chemical
Reaction
Chemical
Equation
Representation of a chemical reaction that
uses symbols to show the relationship
between reactants and products
Reactant
Product
Coefficient
Subscript
Catalyst
Small number in a chemical equation that
comes after a certain element and tells you
how many atoms of that element you have
Example
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Inhibitor
Endothermic
Rxn
Exothermic Rxn
Rxn in which energy is released to the
surrounding environment as heat
Decomposition
Rxn
Synthesis Rxn
Combustion Rxn
Oxidation rxn of an organic compound
where heat is released
Single
Replacement
Rxn
Double
Replacement
Rxn
Rxn in which a gas, solid, or compound
forms from the exchange of atoms or ions
between two compounds
Nuclear Reaction
Photosynthesis
Cellular
Respiration
Section 1:
Key Ideas:
•
Vocabulary:
•
•
•
•
What kinds of bonds form in chemical reactions?
Chemical bonds
Valence electrons
Ionic bonds
Covalent bond
- Molecule
- Compound
- Metallic Bond
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How do atoms (like H2O) stay together?
 Chemical Bonds
o A force of _____________ that holds two atoms together
o Has a significant effect on chemical and physical properties of compounds
o Involves the _______________
 Valence Electrons: the electrons in the outermost energy level of an atom that
______________________________________________________________
Counting Valence Electrons (Draw and Label each picture)
Determining the Number of Valence Electrons by Using the Periodic Table
*Atoms of elements in Groups 1 and 2 have the same number of valence electrons as their group
number (so 1 or 2)
*Atoms of elements in Group 3-12 do not have a general rule relating their valence electrons to
their group number. However, they typically have between 1 or 2 valence electrons.
*Atoms of elements in Groups 13-18 have 10 fewer valence electrons than their group number.
(Exception - helium atoms have only 2 valence electrons, even though they are in group 18)
How Many Valence Electrons? How do you know?
Hydrogen
Lead
Xenon
Sulfur
Rubidium
The Octet Rule
___________________________________________________________________________
___________________________________________________________
Atoms with less than 4 electrons tend to ______ electrons.
Atoms with more than 4 electrons tend to _______ electrons.
Atoms with exactly 4 electrons tend to ____________ electrons.
There are always exceptions!
•
What happens with an atom like Hydrogen, who only has 1 electron, and only needs 2 to
fill its outer shell? ________________________________________________________
________________________________________________________________________
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The Octet Rule In Action – Draw and describe how Sodium and Chlorine combine.
Lewis Structure - (Electron Dot Diagram)
o A way of drawing the outer energy level electrons (valence) of an atom
o The symbol for the element surrounded by as many dots as there are electrons in its outer
energy level (valence)
Examples: Draw Al, N and Mg. How many valence electrons does each have?
3 Types of Chemical Bonds
What can you describe about each of these types of bonds just by looking at the name?
 Ionic:____________________________________________________
 Covalent: _________________________________________________
 Metallic: __________________________________________________
IONIC BONDS
o ________________________________________________________________________
o ________________________________________________________________________
o Forms between atoms of _______________ and atoms of ___________________
o Resulting compounds have a name that usually ends in _______
o ____________ not ______________!
o Example: ________________________________________________________
COVALENT BOND
o ________________________________________________________________________
________________________________________________________________________
o Each pair of shared electrons creates a bond
o ________________________________________________
o Example:
________________________________________________________________________
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Types of Covalent Bonds
Different covalent bond types share a different number of electrons – Draw and label the
examples
METALLIC BOND
o A force of attraction between a positively charged metal ion and the electrons in a
metal
o ________________________________________________________________________
o Many properties of metals, such as conductivity and malleability, result from the freely
moving electrons in the metal
RESULTS OF BONDING
Molecule
Compound
_______________________________
_______________________________
_______________________________
_______________________________
_______________________________
_______________________________
_______________________________
_______________________________
_______________________________
_______________________________
Diatomic - molecules consisting of
two atoms of the same element
bonded together
Examples:
_______________________________
Examples:
H2, F2, O2, N2
•
SECTION 2:
Key Ideas:
•
When do chemical reactions take place?
•
What is the role of energy in chemical reactions?
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•
•
•
•
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What is a chemical equation?
How do I understand what a chemical equation is telling me?
What is photosynthesis? What are the reactants and products?
What is cellular respiration? What are the reactants and products?
Vocabulary:
• Chemical Reactions
• Chemical Equation
• Reactant
• Product
• Coefficient
• Subscript
- Endothermic Rxn
- Exothermic Rxn
CHEMICAL REACTIONS (RXN):
• Chemical Change occurs
• ________________________________________________________________________
________________________________________________________________________
• One or more substances change to produce one or more different substances
• ________________________________________________________________________
• Many forms of energy can be used:
• ____________________________________
• ____________________________________
• ____________________________________
• ____________________________________
•
________________________________________________________________________
________________________________________________________________________
Remember!!!
___________________________________________________________________________
___________________________________________________________________________
Reminder:
CHEMICAL CHANGE:
• a change in which a substance becomes another substance having different properties
• a change that is not reversible using ordinary physical means
• Changes that usually cause, heat, sound, light, odor, fizzing/foaming, color changes
CHEMICAL EQUATION:
• Shorthand form for writing what compounds are used to begin the reaction and what
compounds are formed after the reaction occurs
• Examples:
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2H2 + O2  2H2O
CH4 + 2O2  CO2 + 2H2O
C6H12O6 + 6O2  6CO2 + 6H2O + energy
PARTS OF A CHEMICAL EQUATION: Label them all!
•
______________________
____________________
2H2 + O2
2H2O
What does a Coefficient mean? ____________________________________________
________________________________________________________________________
•
What does a subscript mean? _____________________________________________
________________________________________________________________________
•
What does “Yield” mean? _________________________________________________
•
Reactants are always on what side of the yield sign? ___________________________
•
Products are always on what side of the yield sign? ____________________________
SYMBOLS OF A CHEMICAL EQUATION:
Example:
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PRACTICE:
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In CO2 (carbon dioxide) how many Carbon atoms are there? How many Oxygen atoms?
________________________________________________________________________
•
In 2NH3, (windex) how many Nitrogen atoms are there? How many Hydrogen atoms?
________________________________________________________________________
•
In H2SO4 (battery acid) how many of each type of atom is there?
________________________________________________________________________
•
In 3CHNaO3 (Alka Seltzer), how many of each type of atom is there?
________________________________________________________________________
•
In C9H8O4 (aspirin), how many of each type of atom is there?
________________________________________________________________________
•
What kind of bonds do you think these all form? Why?
Compound
Type of Bond
CO2
2NH3
H2SO4
3CHNaO3
C9H8O4
WHAT IS PHOTOSYNTHESIS?
•
Photosynthesis is: basically how plants make their own food!
Why?
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How does it work? Draw and label diagram.
Photosynthesis formula:
1. What are the reactants in photosynthesis? _______________________________________
2. What are the products? _______________________________________________________
3. What is the catalyst? _________________________________________________________
WHAT IS CELLULAR RESPIRATION?
•
How cells in organisms use oxygen and sugar to make energy needed for us to survive
•
How does it work? Draw and label diagram.
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Cellular Respiration formula:
1. What are the reactants in cellular respiration? _______________________________________
2. What are the products? _______________________________________________________
HOW ARE PHOTOSYNTHESIS AND CELLULAR RESPIRATION RELATED?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
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ENERGY AND CHEMICAL REACTIONS:
Exothermic Reaction
Endothermic Reaction
•
A chemical reaction in which energy
is released.
•
A chemical reaction in which energy
is absorbed.
•
The products have greater bond
energy than the reactants
•
The products have lower bond
energies than the reactants
C6H12O6 + 6O2  6CO2 + 6H2O + energy
6CO2 + 6H2O + energy  C6H12O6 + 6O2
__________________________
________________________
RATES OF CHEMICAL REACTIONS:
The rates at which chemical reactions can take place are influenced by the following:
•
Temperature –a measure of the average kinetic energy of the particles in a sample of
matter
•
•
Ex. Increasing the temperature when cooking increases reaction rate
Surface area – amount of material that comes into contact with the reactants
•
Ex. Cutting a potato into smaller pieces when cooking (larger surface area
(smaller pieces) increases reaction rate)
•
Concentration – amount of substance per volume
•
Ex. Turning the valve on a gas stove to increase the concentration of methane
molecules (this will increase the rate of rxn)
•
•
Ex. Too much salt in a glass of water will decrease the rate of rxn
Catalysts (enzymes) –___________________________________________________
_____________________________________________________________________
•
Inhibitors – ___________________________________________________________
_____________________________________________________________________
SECTION 3:
Key Ideas:
•
What are different types of chemical reactions?
•
How is a nuclear reaction different than a chemical reaction?
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Vocabulary:
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Synthesis Reaction
- Nuclear Reaction
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Decomposition Reaction
- Fission/Fusion
•
Combustion
•
Single Replacement Rxn
•
Double Replacement Rxn
TYPES OF CHEMICAL REACTION
•
4Types
•
Synthesis (creating)
•
Decomposition (separating)
•
Combustion (burning)
•
Displacement/Replacement (switching)
SYNTHESIS (CREATING)
•
________________________________________________________________________
•
Ex: Synthesis of Carbon Dioxide
2CO(g) + O2(g) → 2CO2(g)
DECOMPOSITION (SEPARATING)
•
_______________________________________________________________________
•
Ex: Electrolysis of water to make hydrogen and oxygen
•
2 H2O ---> 2 H2 + O2
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COMBUSTION (BURNING)
•
______________________________________________________________________
•
Oxygen reacts with another element or compound to form water (H2O), carbon dioxide
(CO2) and heat
•
_______________________________________________________________________
DISPLACEMENT/REPLACEMENT (SWITCHING)
•
Two types: Single replacement and double replacement
•
Single replacement (substitution):
__________________________________________________________________
__________________________________________________________________
•
•
Ex: Zn + 2 HCl → ZnCl2 + H2
•
Ex:
Double Replacement: _______________________________________________
__________________________________________________________________
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Ex: AgNO3 + HCl → AgCl + HNO3
•
Ex: Fe2O3 + HCl → FeCl3 + H2O
CHEMICAL VS NUCLEAR RXN:
Chemical Reaction
•
Atoms are rearranged, and chemical
bonds are broken and reformed
•
New substance is formed
Nuclear Reaction
•
__________________________________
•
Involves at least two nuclei, where one
has to have all its electrons removed, by
bringing it to very high temperatures. Why
must the electrons be removed?
•
A neutron is then “slammed” into another
nucleus, causing the nucleus to break
apart (fission) or combine to create a new
nucleus (fusion)
C6H12O6 + 6O2  6CO2 + 6H2O + energy
(respiration)