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GHW# 7- Louisiana Tech University: Chemistry 100. POGIL Exercise for
Chapter 3. Molecules, Compounds, and Chemical Equations: Naming Molecular compounds.
Why?
How do you identify molecular compounds, ionic compounds and metallic compounds?
How do you give formula and a name to molecular compound or ionic compound?
Why naming molecular compound is a little bit more involved than naming ionic compounds or salts? Why is this so? How does molecular compound such as organic compounds (E.g. hydrocarbons) differ in the terminology for naming? Why is it important to know how to name molecular compounds or ionic compound, covert molecular formula to compound name, and to identify possibility of isomers and be able to apply this knowledge to solve problems?
Learning Objectives
The students should be able to understand the concepts and have working knowledge of the following:’’
1. Writing Molecular and Empirical Formulas (Section 3.3)
 Interpret the meaning of molecular, empirical, condensed, and structural and line formula.
 Get the empirical formula from the molecular formula.
2. Classifying Substances as Atomic Elements, Molecular Elements, Molecular
Compounds, or
Ionic Compounds (Section 3.4)
3. Writing Formulas for Ionic Compounds (Section 3.5)
4. Naming Simple Ionic Compounds (3.5)
5. Naming Ionic Compounds Containing Polyatomic Ions (Section3.5)
6. Naming Molecular Compounds (Section 3.6)
 Naming binary molecular compounds
7. Naming Molecular Compounds (Section 3.6)
 Name chain alkanes including straight-chain alkanes
 Naming unsaturated hydrocarbons
 Isomerism in alkanes
8. Naming Organic Compounds (Section 3.11)
 Name chain alkanes including straight-chain alkanes
 Naming unsaturated hydrocarbons
 Isomerism in alkanes
 Identify the important functional groups in carbohydrates and fats
9. Naming Acids (Section 3.6)
10. Calculating Formula Mass (Section 3.7)
11. Using Formula Mass to Count Molecules by Weighing (Section 3.7)
12. Calculating Mass Percent Composition (Section 3.8)
 Calculate mass percent elemental composition from the formula of a compound
 Use percent composition and molar mass to determine the empirical and molecular

formulas of a compound
Success Criteria
Understand the ways we use to show the formula f a molecular compound, systematic naming of molecular compounds, naming straight chain hydrocarbons, naming branched chain hydrocarbons, constitutional isomers, recognize biologically important elements and biological molecules.
Resources Principles of Chemistry: A Molecular Approach, 2nd Edition-Nivaldo
J. Tro Pearson Prentice Hall
Prerequisites
High school chemistry. Concepts of elements atoms and molecules. Names and symbols of elements.
Bonding types covalent and ionic.
New Concepts
Types of Chemical Compounds
1. Mono atomic elements: nonmetal atoms of an element: E.g. He, Ne
2. Molecular or Covalent Compounds: non -metal + non-metal:E.g. sulfur trioxide-SO3
3. Ionic compounds: metal+ non-metal: E.g. potassium chloride-KCl
4. Metals: metals of an element: E.g. Cu
5. Alloys: metal + metal: bronze-CuxSny
Molecular Compound
A compound made up of two or more atoms of non-metallic elements bound together by shared electrons or covalent bonds. E.g H2O, HCl, NH3, CH4, SO3, CO2. Molecular or covalent compounds are composed of molecule. Molecule is defined as a the smallest particle chemically bound atoms with characteristic composition and structure of the molecular compound.
Molecular formula
Formula indicating the type and number of atoms in a molecule of a covalent compound. E.g. the molecular formula of ethyl amine is C2H7N, which indicates that a molecule contains 2 atoms of carbon, 712 atoms of hydrogen, and 16 atoms of nitrogen atom.
Empirical Formula
The formula of a compound expressed as the smallest possible whole-number ratio of subscripts of the elements in the molecular formula. water hydrogen peroxide
Acetic acid glucose
Molecular Formula
H2O
H2O2
C2H4O2
C6H12O6
Empirical Formula
H2O
HO
CH2O
CH2O
Condensed formulas
Another way for writing out a molecule’s formula emphasizing groups of atoms in the molecule and lumping up groups of atoms: CH3CH2NH2
Structural formula
A structural formula is a diagram that shows how the atoms in a molecule are bonded together. Atoms are represented by their element symbols and covalent bonds are represented by lines.

Line-angle Formula
It is assumed that the reader will recognize that the termination of each line and the junction of one line with another represents a carbon and enough attached hydrogen to provide four bonds around each carbon.
Naming acids
Common acids
Acid
Acid name
HNO3 nitric acid
HNO2 nitrous acid
H2SO4 sulfuric acid
H2SO3 sulfurous acid
H3PO4 phosphoric acid
H3PO3 phosphorous acid
H2CO3 carbonic acid
HC2H3O2 acetic acid
CH3COOH
(organic acid)
Ion
NO3NO2SO42SO32PO43PO33CO32C2H3O2-
Less common iacids
Acid Acid name
HClO4 perchloric
HClO3 choleric
HClO2 chlorous
HClO hypochlorous
HCN
Hydrocyanic
H2S2O3 thiosulfuric
H2O water
H2O2
Hydrogen peroxide
Ion
ClO4ClO3ClO2ClOCNS2O32OHO2-2
CH3COO-
Name of inorganic molecular compounds:
Common Name: Before the rules are made for naming common names were given arbitrarily. E.g.
H2O, water is called Water. The common name must be memorized.
Systematic name of H2O water could have been dihydrogen monoxide.
Systematic Name: A substance is given a name according to certain rules.
E.g. Molecular compound with formula: SO3 is given the name sulfur trioxide.
Ionic compound with formula CaCl2 is given the name calcium chloride not calcium dichloride.
Ionic charge is used to figure out the number atoms of each type. You find that rules for naming are not always followed strictly.
Systematic naming binary molecular compounds
Binary molecular compounds are composed of only two elements. The systematic name is more complicated but it has the advantage that the formula of the compound can be deduced from the

name. Examples are carbon dioxide-CO2, nitrogen monoxide-NO, sulfur hexafluoride-SF6 etc.
Prefixes for naming molecular compounds:
1 mono
3 tri
5 penta
7 hepta
9 nona
2 di
4 tetra
6 hexa
8 octa
10 deca
Naming organic molecular compounds:
Hydrocarbons
Straight-chain alkanes has general formula CnH2n+2. Hydrocarbon with one carbon atom is CH4.
Alkyl groups and substituted alkanes
Alkyl group is obtained by removing a hydrogen atom from an alkane. This vacant bond on the carbon atom could be bonded to any atom or functional group that could form a single bond. Methyl alcohol- CH3OH, Ethyl alcohol- C2H5OH, Propyl chloride- C3H7Cl
Branched-chain alkanes and isomerism
Isomers: Isomers are molecules that have the same molecular formula, but have a different arrangement of the atoms in space. That excludes any different arrangements which are simply due to the molecule rotating as a whole, or rotating about particular bonds.
There are three types: constitutional or stereo.
Stereoisomers: They have same boning but different distribution in space and that could be sterogeometrical and optical isomers we will learn later in organic chemistry.
Constitutional Isomers: They have the same molecular formula (that is the same number of atoms of each element represented in the molecule) but these compounds differ in the way the atoms are connected in three dimensional space. Constitutional isomers often vary dramatically in their physical and chemical properties.
E.g. CH3-O-CH3 (methyl ether) and CH3-CH2-OH (ethyl alcohol).
CH3-CH2-CH2-CH3 (n-butane) and (CH3)2-CH-CH3 (isobutane)
Alkanes and Isomers (Section 3.4)
Prefixes
Number of
Molecular Formula
Name of Alkane
Carbon AtomsCnH2n+2
Name of Alkyl Group
Isomers if branching is possible meth- 1

Aldehydes
CnH2n+1-H
R-Cl
R-OH
R-O-R’
R-COOH
R-NH2
R-(C=O)-R’
R-CHO
-ane
-halide
-ol
-ether
-oic acid
-amine
-one
-al
CH3-H
C2H5-Cl
C2H5-OH
C2H5-O-CH3
C3H7-COOH
C3H7-NH2
CH3(C=O)CH3
C2H5-CHO meth-ane ethyl chloride ethyl alcohol
Ethylmethyl ether
Butan-oic acid propyl amine propan-one
1
CH4 methane methyl- CH3
1 eth - 2
2
C2H6 ethane
Ethyl- C2H5
1 prop- 3
3
C3H8 propane
Propyl- C3H7
1 but- 4
4
C4H10 butane
Butyl- C4H9
2
5-penta, 6-hexa, hepta, 8-octa, 9- nona, 10-deca
Classifying Organic Compounds: Functional groups
Hydrocarbons
Organohalide
Alcohols
Ethers
Acids
Amines
Ketones

propan-al
Biomolecules: Carbohydrates, Fats and Proteins
What are carbohydrate, fat (lipids), fatty acid, salt of a fatty acid, amino acid and proteins?
Carbohydrates: Organic compound consisting of a chain of carbon atoms to which hydrogen and oxygen are attached in a 2:1 ratio, E. g, sugars, starch, glycogen, cellulose. Most (but not all) carbohydrates have the empirical formula CH2O. E.g Glucose-C6H12O6
Fat: soft greasy substance occurring in organic tissue and consisting of a mixture of lipids (mostly triglycerides. Triglyceride is made up of fatty acid and glycerin.
Fatty acid: A carboxylic acid (an acid with a -COOH group) with long hydrocarbon side chains.
Saturated fatty acid: A fatty acid carrying the maximum possible number of hydrogen atoms (It doesn't have any double bounds). Unsaturated fatty acid: a fatty acid with one or more double bounds.
Unsaturated fatty acid: A fatty acid with one or more double bounds.
Amino acid: Any of a class of 20 molecules that are combined to form proteins.
Protein: The amino acids condensed into a sequence of amino acids are a protein. The sequence is determined by the genetic code (DNA).
GHW#7 Name:________________________ Date submitted:_________Group:_______
Chapter 3. Nomenclature of Molecular Compounds
Key Questions (relatively simple to answer using the Focus Information)
H2O, Na3PO4, HCl, C2H6, NH3, KCl, CH4, NH4Cl, C6H12O6, Brass-CuxZny, SO3,
NaCl, CO2
1. Identify the types of compounds in the above list: a) Molecular compound: b) Ionic compound: c) Alloy: d) Organic: e) Inorganic:
2. Which of the above compounds have a) Molecular formula: b) Ionic formula: c) Distinct empirical formula:
3. Indicating the type and number of atoms in a molecule of the covalent compound: C6H12O6 . a) C: b) H: c) O: d) Molecular formula: e) Empirical formula:
4. Give systematic names to following binary inorganic molecular compounds a) H2O: b) HCl: c) SF6: d) BF3: e) N2O4: f) CCl4: g) SO3: h) PCl3:
5. Give the common name of the following molecular compounds a) NH3: b) CH3COOH: c) C6H12O6: d) C2H5OH:
6. Give the names of the following acids
Formula
Name

a) HNO3: c) HNO2: e) H2SO4: g) H2SO3:
Ion (s)
Formula b) d) f) h)
Name
Ions(s)
H3PO4:
H3PO3:
H2CO3:
CH3COOH:
7. Given the structural formula of an organic compound, write the for the following:
CH3CHClCH2OH a) molecular formula b) condensed formula c) structural formula d) line formula
8. Name, molecular, condensed and line formula of straight chain alkane
(saturated hydrocarbons) or n-alkanes. a) 4 carbon n-alkane: b) 7 carbon n-alkane:
9. Draw the structural formula of constitutional isomers of butane with molecular formula C4H10. a) n-butane: CH3CH2CH2CH3 b) isobutene: (CH3) 3CH
10. Classification and the name of the following organic compounds
Classification
Name a) CnH2n+2 where n is 8: b) CH3CH2CH2CH2-OH: c) CH3CH2CH2-COOH: d) CH3CH2CH2CH2CH2CH2-NH2: e) CH3CH2-(C=O)-CH3: d) CH3CH2-CHO:
11. Identify the classification or name of the following biologically important molecules a) b) c) d) e) f)
1.
2.

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