Download Chapter 3: Molecules, Compounds and Chemical Equations

Chemistry 1A: Chapter 3 Part A
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Chapter 3: Molecules, Compounds and Chemical Equations:
Nomenclature, sections 3.1-3.6, 3.11
Homework:
Read Chapter 3: Work out sample/practice exercises.
Memorize the polyatomic ions, diatomic elements, prefixes for binary molecules, the
first ten alkanes, and the Nomenclature rules of naming.
Bonus Chapter 3 Problems:
23, 29, 33, 39, 41, 43, 45, 49, 51, 55
Check for the MasteringChemistry.com assignment and complete before due date
Pure Substances and Mixtures:
Pure substances have one invariable composition (elements and compounds)
Mixtures have a variable composition. Homogeneous mixtures (solutions) are
those in which the mixing is uniform throughout the mixture (coffee, salt water,
air) while Heterogeneous mixtures are those in which the mixture is not
uniform, they vary in texture and have regions of different composition (soil,
pencil). This section will give the rules on how to name simple pure substances.
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Chemical Bonds:
Covalent bonds share electrons and are found in molecules made up when two
or more nonmetals combine.
Ionic bonds transfer electrons and are found in compounds made up from
combining cations (metals, positively charged) with anions (nonmetals,
negatively charged). The cation is always before the anion in the formula. The
net charge of the compound is zero.
Propane, C3H8
Sodium Chloride, NaCl
Acids and Bases:
Acids are substances that increase H+1 ions in water. The cation is H+1.
Bases are substances that increase OH-1 ions in water. The anion is often OH-1.
Structural Formula will show the specific connections between atoms within a molecule
and gives more information than a chemical formula alone.
Chemistry 1A: Chapter 3 Part A
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Empirical Formula is the simplest whole number ratio between atoms.
Nomenclature:
Elements
Most elements are written in an atomic form and given the element name: Cucopper, He-Helium, Zn-zinc
Seven elements are diatomic and are called by their element name:
H2-hydrogen, N2, O2, F2, Cl2, Br2, I2
A couple are polyatomic:
P4 is phosphorus, S8 is sulfur
Some elements form more than one molecule/structure (allotropes)
O2 is oxygen, O3 is ozone; C(graphite), C(diamond), C60
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Common names
Some molecules have been around so long they go by a common name:
H2O-water, NH3-ammonia, CH4-methane, SiH4-silane
Binary molecules
CO2, P2O4, CCl4
Mono, di, tri, tetra, penta, hexa, hepta, octa, nona, deca
Prefix (not mono) element name prefix root of element plus ide
Carbon dioxide
Drop the a before an o, pentoxide, not pentaoxide.
Organic molecules
Alkanes (CnH2n+2)
Methane CH4, ethane C2H6, propane C3H8, butane C4H10, pentane
C5H12, hexane C6H14, heptane C7H16, octane C8H18, nonane C9H20,
decane C10H22
Functionalized hydrocarbons: alcohol, ether, aldehyde, ketone, carboxylic
acid, ester amine to name a few.
Alcohols (replace one H in alkane with an OH)
Methanol, CH3OH; propanol, C3H7OH
Carboxylic acids ( X–COOH, where the C is both double bonded to one O
and single bonded to an OH). These compounds generally use their
common name
HCOOH; formic acid and also known as methanoic acid
CH3COOH or HC2H3O2; acetic acid, also known as ethanoic acid
Ionic compounds (write cation name then anion name)
Cations with known oxidation state of metal
Group 1A (+1), 2A (+2) , Al and Ga (+3), Zn and Cd (+2), Ag (+1)
Name of ion is identical to the name of the atom for cations
Variable oxidation state of metal
Transition metals and metals below the nonmetal on the right have a
variable oxidation state that must be indicated by Roman Numerals in
parenthesis (this method is what I expect you to learn.
Fe+3, iron (III); Fe+2, iron (II); Cu+1, copper (I); Sn+4, tin (IV)
An alternative method differentiates from the higher oxidation number
and lower oxidation number using the old form of the name and ic or
Chemistry 1A: Chapter 3 Part A
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ous as an ending respectively. (you should be aware of this method, but
it will not be on a test)
Fe+3, ferric Fe+2, ferrous; Cu+2, cupric; Cu+1, cuprous; Sn+4, stannic;
Sn+2, stannous.
Elemental Anions
Group VA (-3); VIA (-2), VIIA (-1)
Name of the element root followed by ide.
N-3, nitride; S-2, sulfide, Br-1, bromide
Polyatomic cations and anions
Memorize the polyatomic ions and be able to evaluate ion names,
formulas, and charges following some basic rules.
Acids
Binary acids-H+ cation and an anion that ends with ide.
Hydro root of element ic acid. H2S, hydrosulfuric acid
Ternary oxyacids-H+1 cation with and anion ending in ate or ite
ate changes to ic acid, do not use hydro
H2SO4 becomes sulfuric acid
ite changes to ous acid, do not use hydro
H2SO3 becomes sulfurous acid
Hydrates
Ionic compounds can be chemically attached to a small number of water
molecules in a solid form. CuSO4.5H2O, copper (II) sulfate pentahydrate
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Nomenclature Practice:
Fill in the table with formulas and names of the ionic compounds.
Cl*
CO3-2
AsO4-3
H+1
Zn*
Fe+3
Sn+4
NH4+1
Al*
*predict the known oxidation number
OH-1
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Nomenclature Practice:
Names
Formulas
Aluminum sulfide
Sodium carbonate
Tetraphosphorus decoxide
Nickel (II) chloride
Butane
Ammonium phosphate
Ethanol
Hydrosulfuric acid
Sulfuric acid
Sulfurous acid
Cobalt (II) chloride hexahydrate
H3PO4
H2C2O4 (aq)
H2O2
HBr (g)
HBr (aq)
CCl4
C8H18
VClO3
CuCr2O7
(NH4)2HPO4
KMnO4