2. How to study
• Much memorization, BUT…..
• Learn the process of thinking like CHEMIST
• Understand, absorb and apply principles
• Practice actively –models, problems, summaries, flow charts
• Small steps and frequent study – you CAN’T cram right before the exam
• Be prepared to fail and to regroup – you need to develop a new method
of learning
• Get help! - study group,
3. Study plan
Date Time Module Content/topic Summary Challenges Solution
First 4 columns form part of your time table
5. Organic Compounds Inorganic Compounds
Use mostly covalent bonding Mostly ionic bonding
Are gases, liquids or solids with low melting
points
Are generally solids with high melting points
Mostly insoluble in water Many are water soluble
Many are soluble in organic solvents such as
petroleum, benzene and hexane
Most are not soluble in organic solvents
Solution in water generally do not conduct
electricity
When dissolved in water conducts electrical
current
Almost all burn Most not combustible
Slow to react with other chemicals Often undergo fast chemical reactions
6. Why does carbon form so many compounds?
• Carbon has the ability to bond with itself to form long chains,
branched structures and ring structures; hence it can form molecules
that contain from one to an infinite number of C atoms.
7. Why does carbon form so many compounds?
Additionally C atoms may:
be bonded by multiple bonds (i.e. double and triple)
8. Why does carbon form so many compounds?
Additional atoms may be attached to them to make them stable. The
most common of these is H, but, N, O, X, P and S also commonly occurs
attached to C and may even be attached in several different ways. Note
X is the symbol for any of the halides – F, Cl, Br or I
12. The Rules for Drawing Organic Molecules
1. C always has four bonds. This may consist of:
• 4 single
• 1 double and 2 single
• 1 triple and 1 single
• 2 double
2. H always has one bond.
3. O always has two bonds. This may consist of:
• 2 single
• 1 double
13. The Rules for Drawing Organic Molecules
4. X always has one bond. X = F, Cl, Br or I
5. N always has three bonds. This may consist of:
• 3 single
• 1 single and 1 double
• 1 triple
6. S may have 2, 4 or 6 bonds, but for this course it has 2 bonds.
14. Types of formulae of organic compounds
• General formula eg CnH2n + 2
• Molecular formula eg C4H10
• Structural formula eg
• Condensed structural formula
16. Information Overload vs Quick and Easy
• In a line-bond structure you see EVERYTHING (except for lone pairs,
actually).
• All atoms must be drawn into the structure. C6H14
• Ex:
• These can take a long time to draw!
C C C C C
C
H
H H
H
H
H
H
H
H
H
H
H
H
H
17. Different Ways to Write Butane
Look at this! CH3CH(CH3)CH3 Look at this! CH3CHCHCH3
18. Which is cleaner and more concise?
• Skeletal structures are perhaps a little confusing… Seems like things
are missing…
• Once you know the rules, skeletal structures are actually much easier
to draw!
OR
skeletal
C
C
C
C
C
C
C
C
C
H
H H
H H
H H
H
H
H
H
H
H
H
H
H
H
H
H H
line bond
19. Skeletal Structures
• Skeletal structures are those “zig-zag” structures you see quite often.
• “Zig-zag” is required so you can see connectivity… lines that are
“straight on” may be confusing:
vs
(there are 2 here!)
20. Skeletal Structures - Rules
• In order to understand HOW to draw molecules using these zig-zag
lines, you need to follow a certain set of rules, or else none of it
makes any sense
• We will start by converting to line-bond structures that show
everything.
21. Skeletal Structures – Rule #1
• Rule #1: never draw a “C” to represent a carbon atom (as in C-H or C-
C or C=C…)
• When doing shorthand notation like this, “less” is faster to draw, so
ditch those “C”s!
22. Skeletal Structures – Rule #2
• Rule #2: At the end of any line, you will always assume there is a C, if
no other atom is shown.
• Take this single line, the simplest skeletal structure possible:
• How many carbons do you “see”?
23. Skeletal Structures – Rule #2
• If the end of a line represents a carbon atom, then you will “see” a
carbon at each end of the line:
• That line represents:
C C
24. Skeletal Structures – Rule #3
• Rule #3: At the intersection of two or more lines, assume there is a C,
if no other atom is shown.
• Now take this skeletal structure:
• How many intersections are there?
25. Skeletal Structures – Rule #3
• There are two lines connecting in the center to form one intersection:
• That intersection represents a carbon atom, without having to draw the
C’s.
• Up to four lines may connect to intersect.
26. Skeletal Structures – Rules 2 and 3
• How many total carbons are in this molecule?
• You have to count all intersections and the ends of any lines to get
the total number of carbons represented.
27. Skeletal Structures – Rules 2 and 3
• So, how many total carbons are in this molecule?
• One intersection plus two ends of lines adds up to
three total carbon atoms:
C
C
C
end
end
intersection
29. Skeletal Structures – Rules 2 and 3
• How many total carbons are in this molecule?
• Five carbons total:
end
end
end
intersections
C
C
C
C
C
30. Skeletal Structures – Rules 2 and 3
• One more time, how many total carbons are in this molecule?
31. Skeletal Structures – Rules 2 and 3
• One more time, how many total carbons are in this molecule?
• Five end carbons…
end
end
end
end
end
32. Skeletal Structures – Rules 2 and 3
• …and four intersecting carbons…
• …for a grand total of 9 C’s you didn’t have to draw!
C
C
C
C
C
C
C
C
C
33. Skeletal Structures – Rule #4
• Rule #4: The “H” of a hydrogen attached to carbon is not drawn.
• Just remember that carbons must have four bonds. Count bonds and
subtract from 4 – that will be the number of H’s.
• Take this skeletal structure again:
• How many hydrogen atoms are on each carbon?
34. Skeletal Structures – Rule #4
• Recall that there are C’s at the end of each line.
• The left-hand C has one bond (to the right-hand C). This means that,
by default, it must have 3 hydrogen atoms attached (4 total minus 1
to a C = 3 H)
• The right-hand C also has one bond to a C. This means that it too also
must have 3 hydrogen atoms attached (4 total minus 1 to a C = 3 H)
C C
equals
35. Skeletal Structures – Rule #4
• Final structure?
• The skeletal structure on the left was WAY easier to draw… With
practice, you’ll get used to this process…
C C
equals equals C C
H
H
H
H
H
H
36. Skeletal Structures – Rule #4 again
• Take this skeletal structure:
• How many hydrogen atoms are on each carbon?
37. Skeletal Structures – Rule #4
• Left carbon – one line
• Right carbon – one line
• Center carbon – two lines
• Left carbon – 4-1 = 3 H
• Right carbon – 4-1 = 3 H
• Center carbon – 4-2 = 2 H
39. Try another molecule
• Convert the following skeletal structure to a line-bond structure:
• Add C’s to “ends” and “intersections” and then determine how many
H’s are attached to each. Don’t move forward until you’ve drawn it!
40. Answer?
• These two are the same molecule:
equals C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H H
H
H
H
H
H
H
41. Answer?
• Remember that your answer may look similar but not exactly the
same.
• What counts is that you have the C’s labeled correctly and you have
the right number of H’s on each C. For instance, my C(#1) has to have
3H’s, C(#2) has to have 2 H’s, C(#3) has to have 1 H, etc…
equals C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H H
H
H
H
H
H
H
1
2
3
6
4 5
7
1
2
42. Skeletal Structures - Rule #5
• Rule #5: Everything besides C-H and C-C must be shown. These other
atoms (like O, N, F, Cl, Br, etc) must be shown.
• Note that Hydrogen atoms can and should be shown for these other
atoms and even C=C has to be drawn, even when C-C does not.
OH O
43. Line-Bond to Skeletal Structure
• Now that you have a sense of what skeletal structures equate to, let’s
try the other direction…
• A skeletal structure is a line-bond structure without its letters.
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
44. Line-Bond to Skeletal Structure
• So you need to simplify. Start by removing all those H’s on the C’s…
C
C
C
C
C
C
C
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
45. Line-Bond to Skeletal Structure
• Then erase all those C’s…
• Good job… Try the next one!
C
C
C
C
C
C
C
46. Line-Bond to Skeletal Structure
• Convert the following to a skeletal structure:
• Erase the C-H bonds, then the C’s…
C
C
C
C
C
C C
C
Br
H
H
H
H
H
H H
H H
47. Line-Bond to Skeletal Structure
• Leave the Br though!
C
C
C
C
C
C C
C
Br
H
H
H
H
H
H H
H H
C
C
C
C
C
C C
C
Br
Br
48. Line-Bond to Skeletal Structure
• Convert the following to a skeletal structure:
C
C
C
C
C
C
Cl
C
H
H
H
H
H
H
H
H
H
H
H
H
H
49. Line-Bond to Skeletal Structure
• Erase the C-H bonds, then the C’s… but leave the Cl!
Cl
C
C
C
C
C
C
Cl
C
H
H
H
H
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
Cl
C
50. And in the other direction…
• Obviously, you need to put the letters back into place, alone with the
C-H bonds…
• Draw the Line-Bond structure for:
• Find ends and intersections first…
51. Skeletal to Line-Bond…
• Ends in blue… intersections in red…
• Triple bonds are a bit confusing at first – the intersection is actually
straight, when drawn correctly:
So, put in the C’s…
52. Skeletal to Line-Bond…
• And now you have:
• Now add in the C-H bonds. Every C must have a total
of four lines.
C
C
C
C
C
C
53. Skeletal to Line-Bond…
• Finished Line-Bond Structure:
• Notice how the one end of the triple bond, the red
carbon, already has four bonds so no bonds to H for
that carbon!
C
C
C
C
C
C
H
H
H
H
H H
H H
H H
54. Skeletal to Line-Bond or V.V
• These take practice… Once you’ve mastered the
basics of the skeletal structure you are ready to make
the leap to converting skeletal structures to
condensed formulas and back again…
• When you are ready, go check out the next
PowerPoint – Skeletal to Condensed and Back Again
57. Number
of carbons
Prefix as
in new
system
Number
of carbons
Prefix as
in new
system
Number
of carbons
Prefix as
in new
system
Number
of
carbons
Prefix as in
new system
1 meth- 10 dec- 20 eicos- 30 triacont-
2 eth- 11 undec- 21 uncos- 31 untriacont-
3 prop- 12 dodec- 22 docos- 32 dotriacont-
4 but- 13 tridec- 23 tricos- 33 tritriacont-
5 pent- 14 tetradec- 24 tetracos- 34 tetratriacont-
6 hex- 15 pentadec- 25 pentacos- 35 pentatriacont-
7 hept- 16 hexadec- 26 hexacos-
8 oct- 17 heptadec- 27 heptacos- 40 tetracont-
9 non- 18 octadec- 28 octacos- 50 pentacont-
19 nonadec- 29 nonacos-
58. NAMING - prefix alk suffix
• Principal the functional group
• Parent chain with the functional group – maximum length, highest number of
substituents, principal in cyclic makes cyclic principal
• Name the parent and structure and principal group -alk suffix
• Number from end with nearest to the main functional group (highest priority) – if
this is obtained from both directions then try to achieve the lowest total, if first
substituents occur at equal distances then check the second substituent – look
for any difference that will result PRIORITY
59. NAMING - prefix alk suffix
• Name alkyl, halides etc – show the position
• Double and triple bond are part of the main chain
• Hyphen between a number and a word. Comma between numbers
• Substituents with the same priority are put alphabetically in the name
• Substituents are put in priority
• (study well how the substituents are named)
