Types of Chemical Bonds- 11/18/14 Compound- substance made of
the combined atoms of two or more elements Chemical formula- tells
what elements a compound contains and the exact number of the atoms
of these elements
Slide 4
Atoms form compounds to become chemically stable. An atom is
chemically stable when the outer energy level is complete, or full.
Some Common Compounds VinegarAcetic acidHC 2 H 3 O 2 SandSilicon
dioxideSiO 2 Stomach AcidHydrochloric acidHCl Cane SugarSucroseC 12
H 22 0 8
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Chemical bond- force that holds together the atoms in a
substance Ionic BondCovalent Bond Loses or gains electrons
Attraction between opposite charges of ions Between metal &
nonmetal Shares electrons Can form multiple bonds Between a
nonmetal and a nonmetal * ION- positive or negatively charged
atom
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Ionic and Covalent Bonding
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Question: What would a chemist name the compound CuCl?
Slide 8
Writing Formulas & Naming Compounds - 11/20/14 Binary
compound- compound composed of two elements Oxidation number-
positive or negative number which indicates how many electrons an
element has gained, lost or shared when bonding with another atom
*When writing formulas for binary ionic compounds, it is important
to remember that compounds formed have a net charge of zero.
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Polyatomic ions- a positively or negatively charged covalent
bonded group of atoms *The prefix poly means many, so the term
polyatomic means having many atoms Polyatomic Ions
ChargeNameFormula 1+AmmoniumNH 4 + 1AcetateC2H3O2C2H3O2
1ChlorateClO 3 1HydroxideOH 1NitrateNO 3 2CarbonateCO 3 2
2SulfateSO 4 2 3PhosphatePO 4 3
Slide 11
Hydrate- compound that has water chemically attached to its
ions and written into its chemical formula. Covalent compounds can
form more than one compound with each other. Scientists use Greek
prefixes to indicate # of atoms of each element in binary compound.
Prefixes for Binary Covalent Compounds # of Atoms 12345678
PrefixMono-Di-Tri-Tetra-Penta-Hexa-Hepta-Octa-
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Question: Why do chemical equations need to be balanced?
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Chemical Reactions - 12/2/14 Chemical reaction- a reaction in
which one or more substances are changed to new substances
Reactants- substances that are about to react Products- new
substances produced Law of Conservation of Mass- total starting
mass of all reactants equals the total final mass of all products.
Reactants Produce Products
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Chemical equation- uses chemical formulas and symbols to
describe a chemical reaction and the product it produces
SymbolMeaningSymbolMeaning Produces/yield s (aq)Aqueous (solid
dissolved in H 2 O) +plus Heat Reactants heated (s)solid Light
Reactants exposed to light (l)liquid Elect Electric current applied
to reactants (g)gas
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*Review: Coefficients- numbers which represent the number of
units of each substance in a reaction Subscripts- numbers which
represent the number of atoms in a molecule of a particular
elements
Slide 18
Balancing Chemical Equations- 12/9/14 Balanced chemical
equations- have the same number of atoms of each element on both
sides of equation *When balancing chemical equations NEVER change
the subscripts, instead change the coefficient in front of the
compounds needing to be balanced.
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Steps to Balancing a Chemical Equation 1. Write a chemical
equation for the reaction using formulas and symbolsmake sure
reactants are on left side and products on right. 2. Count the
atoms in reactants and products. 3. Choose coefficients that
balance the equation. Hint: Generally if there is an even # of an
element on one side and an odd on the other side, place a 2 in
front of compound containing odd number of atoms. 4. Recheck the
numbers of each atom on both sides of equation and adjust
coefficients if necessary remember NEVER change subscripts.
Question: What happens to chemical bonds during energy
exchanges?
Slide 22
Chemical Reaction Types- 12/9/14 Synthesis reaction reaction
where two or more substances combine to form another substance A +
B AB Decomposition reaction reaction where one substance breaks
down or decomposes into two or more simpler substances AB A +
B
Slide 23
Single displacement reaction- reaction in which one element
replaced another in a compound. A + BC AC +B or A + BC AB +C
Double-displacement reaction- reaction that results in a
precipitate, water or gas when a positive ion of one compound swaps
with another positive ion of another compound AB + CD AC + BD
Slide 24
Chemical reactions involve energy exchange Exothermic Reactions
Reaction in which energy is released in form of heat Ex. Burning
wood, fireworks, elephants toothpaste Endothermic Reactions
Reaction in which heat energy is absorbed Ex. Chemical ice packs,
photosynthesis Catalyst- speeds up a chemical reaction without
itself being permanently changed Inhibitor- prevents or slows a
chemical reaction or interferes with the catalyst
