Chemistry Chapter 2:
Valences (Charges):
The charge assigned to an atom in a molecule
Sum of valences must be zero
Binary Compounds:
Compounds with only 2 elements
The first element has one possible valence
Naming:
Name first element normally
Change second element ending to “ide”
Formula:
Write symbol of each element
Determine the valence of each element
Criss cross valence use as subscripts
Reduce subscripts to simple ratio
(subscripts of 1 are not written in the final formula)
Multivalent Metals:
Some elements have more than one possible valence
Iron can either be Fe2 Fe3
IUPAC Method:
Compounds with multivalent metals only
Indicate which ion is involved in the compound by putting the charge in brackets after
the name of the metal.
Use roman numerals to indicate the charge (I,II,III,IV,V,VI,VII… )
OUS-IC Method:
Compounds with multivalent metals only
Indicate the higher valence with “ic” ending and the lower valence with “ous” ending
Historic names are often used
Formula
IUPAC Name
OUS-IC Name
CuCl
Copper Chloride
Cuprous Chloride
SbCl3
Antimony (III) Chloride
Antimous Chloride
HgO
Mercury (II) Oxide
Mercuric Oxide
Naming Covalent Compounds- Use Greek Prefix Method:
Use the prefixes to say how many of each atom are present in the compound
One is never used for the first element
Prefixes: Mono, Di. Tri, Tetra, Penta, Hexa
Naming Binary Acids, Bases, and Gases:
Binary Acids:
Two elements
Acids are compounds containing a hydrogen ion and a nonmetal
Bases:
Contain a hydroxide ion bonded to a metal
Diatomic Gasses:
H Hydrogen Gas
O2 Oxygen gas
F2 Fluorine gas
Br2 Bromine gas
I2 Iodine gas
N2 Nitrogen gas
Cl2 Chlorine gas
Polyatomic Ions and Related Oxyacids:
A group of atoms that stay together and have an overall ionic charge
Standard Polyatomic Ions have an “ate” ending
If there is one more starts with “per”
If there is one less end with “ite”
If there is 2 less starts with “hypo” ends with “ite”
(Charge does not change)
Oxyacids:
Add H+ to polyatomic ions
Standard Oxyacids end with “ic”
Is there is one more starts with “per” ends with “ic”
If there is one less ends with “ous”
If there is 2 less starts with “hypo” ends with “ous”
Hydrates:
Have specific number of water molecules in their chemical formulas, as solids these
water molecules are part of the compound’s structure
Naming Hydrates:
The ionic compound is named first using IUPAC naming rules
Greek prefixes are attached to the word “hydrate” to indicate the number of water
molecules attached to each formula unit of the ionic compound.
Formula Of Hydrates:
When writing the chemical formula for a hydrate, the formula for the ionic compound is
separated from the water molecules by a centered “dot”
Equations For Chemical Reactions:
1. Word Equation
2. Skeleton Equation
3. Balance Chemical Equations
Types Of Reactions:
Synthesis Reactions:
Reaction in which 2 or more reactants come together to form one compound
Decomposition Reaction:
Reaction in which one substance is broken down into 2 or more smaller substances
Combustion Reaction:
Reaction of any compound with oxygen
2 main types : metal or nonmetal with O2 , Hydrocarbon with O2 (complete or
incomplete)
Incomplete Combustion: takes place in environments where there is not enough oxygen
gas to produce only CO2
Single Displacement Reaction:
Reaction in which one substance replaces another in a compound
Metals only replace metals
Nonmetals only replace nonmetals
Double Displacement Reactions:
Reaction in which the ions in 2 compounds change places
Metals only replace metals, nonmetal and polyatomic only replace nonmetals and
polyatomics
2 types of double displacement reactions:
Reactions that produce a precipitate as a product
Reactions that produce water these are also called neutralisation reactions occur
between acids and bases or acids and carbonates/bicarbonates
How To Predict the Products of Chemical Reactions:
1) Write the word equation
2) Determine the formulas (make a skeleton equation)
3) Balance the reaction
Single Displacement Reactions:
Predictions can be made based on the activity series of metals
Metal + Acid/Water:
Any metal above hydrogen in the activity series will displace hydrogen gas from an acid
or water, although sometimes heat must be applied to increase the reaction rate to the
point where the reaction is noticeable
Metal + Metallic Compound (aq):
A metal will displace from a compound (in solution) any other metal which is located
below it in the activity series of metals
Nonmetals:
Predictions can also be made based on the activity series of nonmetals
Double Displacement Reactions:
If neither product precipitates out, o reaction occurs
May also produce a gas and/or water