2.1 Chemistry Tutorial
The chemical compounds that are important for understanding most of the chemistry in this course are organic - that means that the compounds primarily contain carbon, hydrogen, and oxygen atoms (also sulfur and nitrogen). They can also be called hydrocarbons. The basic structures that we will be discussing in this course are called: 1) alkane (aka aliphatic), 2) branched alkane, 3) cycloalkane, 4) alkenes (double-bonds), 5) aromatic, 6) hydroaromatic, and 7) alcohols. First, I will show the atoms and how they are connected using the element abbreviation and lines as bonds, and then I will show abbreviated structural representations.
1. Alkane - atoms are lined up. For stick representation, each corner represents a CH2 group, and each end represents a CH3 group.
Name |
Atoms and Bonds |
Stick Representation |
Heptane (7 C atoms) |
![Straight Line of 7 C's connected to each other. The two end C's have 3 H's connected to it and all the others have 2 H's](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/Alkane.jpg) |
![Zigzag line with 7 corners (including the ends). Each corner (including the ends) represent one carbon](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/alkanestickrepresentation.jpg) |
2. Branched Alkane - still an alkane, but instead of a straight line, the carbons are branched off of each other.
Name |
Atoms and Bonds |
Stick Representation |
Isobutane (4 C atoms) |
![Straight line of 3 Cs. The two end C's have 3 H's attached and the middle C has one H and one branch with a CH3 group](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/isobutane.jpg) |
![Three lines making a Y shape. Each end of the Y and the intersection represent a carbon](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/isobutanebranch.png) |
Isopentane (5 C atoms) |
![Straight line of 4 Cs. The 2 end C's have 3H's attached & one of the middle Cs has 1 H and 1 branch with a CH3 group, the other C has 2 H's](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/isopentane.jpg) |
![Zigzag with four corners (including the ends) and one branch of off 1 of the internal corners](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/isopentanebranch.jpg) |
3. Cycloalkanes - again, still an alkane, but forms a ring compound.
Name |
Atoms and Bonds |
Stick Representation |
Cyclohexane (6 C atoms) |
![hexagon with a CH2 at every vertice](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/cyclohexane.jpg) |
![hexagon](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/cyclohexanestick.jpg) |
4. Alkenes - alkanes that contain a double bond.
Name |
Atoms and Bonds |
Stick Representation |
Pentene (5 C atoms) |
![line of 4 Cs connected by single lines (bond) and a fifth C connected with a = (double bond)](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/pentene.jpg) |
![zig zag with 5 vertices including the ends. The last segment of the zigzag is a = (double bond)](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/pentenebranch.jpg) |
5. Aromatic - hydrocarbon ring compound with single and double bonds, significant differences in properties.
Name |
Atoms and Bonds |
Stick Representation |
Benzene (6 C atoms) |
![hexagon with CH on every vertice. Every other edge has a double bond (two lines)](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/benzene.jpg) |
, ![hexagon with a circle inside representing the same as alternating double lines](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/benzenestick2.jpg) |
6. Hydroaromatics - hydrocarbon ring compound with an aromatic and an alkane in one molecule.
Name |
Atoms and Bonds |
Stick Representation |
1,2,3,4-tetrahydronaphthalene, aka tetralin (10 C atoms) |
![hexagon with alternating double bonded sides connected along a single bonded side to a hexagon with single bonds](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/tetralin.jpg) |
![hexagon with a circle inside connected along one side to a hexagon](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/tetralinstick.jpg) |
7. Alcohols - hydrocarbon with -OH functional group.
Name |
Atoms and Bonds |
Stick Representation |
Butanol (4 C atoms) |
![Line of 4 Cs in a row. The first C has 3Hs the last 3 have 2Hs connected and the final C also has an -OH connected](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/butanol.jpg) |
![Zig zag with 5 vertices including the ends. One of the end vertices has an OH attached to it](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/butanolstick.jpg) |
Ethanol (2 C atoms) |
![A CH3 connected to a CH2 connected to an -OH](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/ethanol.jpg) |
![zig zag with 3 corners including the ends with an OH connected to one end corner](/egee439/sites/www.e-education.psu.edu.egee439/files/wysiwyg_template_images/Images/ethanolstick.jpg) |
The following table shows common hydrocarbons and their properties. It is important to know the properties of various hydrocarbons so that we can separate them and make chemical changes to them. This is a very brief overview - we will not yet be going into significant depth as to why the differences in chemicals affect the properties.
List of Common Hydrocarbons and Properties
Name |
Number of C Atoms |
Molecular Formula |
bp
(°C), 1 atm |
mp
(°C) |
Density
(g/mL) (@20°C) |
Methane |
1 |
CH4 |
-161.5 |
-182 |
-- |
Ethane |
2 |
C2H6 |
-88.6 |
-183 |
-- |
Propane |
3 |
C3H8 |
-42.1 |
-188 |
-- |
Butane |
4 |
C4H10 |
-0.5 |
-138 |
-- |
Pentane |
5 |
C5H12 |
36.1 |
-130 |
0.626 |
Hexane |
6 |
C6H14 |
68.7 |
-95 |
0.659 |
Heptane |
7 |
C7H16 |
98.4 |
-91 |
0.684 |
Octane |
8 |
C8H18 |
125.7 |
-57 |
0.703 |
Nonane |
9 |
C9H20 |
150.8 |
-54 |
0.718 |
Decane |
10 |
C10H22 |
174.1 |
-30 |
0.730 |
Tetradecane |
14 |
C14H30 |
253.5 |
6 |
0.763 |
Hexadecane |
16 |
C16H34 |
287 |
18 |
0.770 |
Heptadecane |
17 |
C17H36 |
303 |
22 |
0.778 |
Eicosane |
20 |
C20H42 |
343 |
36.8 |
0.789 |
Cyclohexane |
6 |
C6H12 |
81 |
6.5 |
0.779 |
Cyclopentane |
5 |
C5H10 |
49 |
-94 |
0.751 |
Ethanol |
2 |
C2H6O |
78 |
-114 |
0.789 |
Butanol |
4 |
C4H10O |
118 |
-90 |
0.810 |
Pentene |
5 |
C5H10 |
30 |
-165 |
0.640 |
Hexene |
6 |
C6H12 |
63 |
-140 |
0.673 |
Benzene |
6 |
C6H6 |
80.1 |
5.5 |
0.877 |
Naphthalene |
10 |
C10H8 |
218 |
80 |
1.140 |
1,2,3,4-Tetrahydronaphthalene |
10 |
C10H12 |
207 |
-35.8 |
0.970 |