1. Organic Chem Class #2 OB: we’ll have a brief review of alkanes, then, master alkenes, and alkynes. At the end of today you should be able to name and draw, and recognize any alkane, alkene, or alkyne from 1 to 10 carbons long.

2. Between tables P + Q you should be able to draw all 10 alkanes. Yesterday we did the first 5, let’s finish up the rest quickly. Write name + formula, then draw the structural diagrams. You may omit the “H” atoms, but you may not forget that they are there!

3. The 2 nd type of hydrocarbon chains are called alkenes. Their general formula is C n H 2n They have less hydrogens than the alkanes because they contain 1 double bond. In our class they will contain JUST 1 double bond, but in the real world, more than one double bond is possible. We will draw the first three in a row now… Try that “methene” but don’t get frustrated, it’s not possible. You need at least 2 carbons to have a double bond between 2 carbon atoms! Now go for ethene and propene…

4. Ethene Hydrogen atoms at an angle is cool, or you can stick with the 90° angles, it’s just a drawing. Propene Straight lines, or bent, the chain is 3 carbons in a row and that’s all that matters. Double bond left or right, it’s the same thing, molecules float!

5. Try to draw butene now.

6. With 4 carbons things start to get a touch more complicated. You can you put that double bond in 2 different places (between carbon 1 + 2, or between carbon 2 + 3) Where is that double bond? It’s attached to which carbon atoms? It’s crooked, but still a line. Where is that double bond? How do we tell these apart?

7. The carbon atoms need to be named 1, 2, 3, and 4. The “rule” is that the carbon atom closest to the double bond is #1. So, the first molecule has carbon #1 on the left. The double bond is between carbon #1 and #2, so we’ll call it 1-butene. This one at right has the double bond between the 2 nd and 3 rd carbon. Note that from EITHER SIDE that is true. You could call the left carbon #1, or the far right hand carbon #1, but the double bond still attaches carbon #2 to carbon #3 This one is 2-butene.

8. Draw the following (you MAY omit the “H” atoms, but not the bonds 1-pentene 2-pentene 3-hexene 3-heptene 3-octene 4-nonene And 1-decene

9. Draw the following (you MAY omit the “H” atoms, but not the bonds 1-pentene 2-pentene 3-hexene 3-heptene

10. Draw the following (you MAY omit the “H” atoms, but not the bonds 3-octene -c-c-c = c-c-c-c-c- 4-nonene -c-c-c-c = c-c-c-c-c- 1-decene

11. The third group of hydrocarbons are the ALKYNES Small change in name, this one has a triple bond. In our class the ALKYNES will ONLY have one triple bond. Naming and drawing will be just like the alkynes, the bond placement must be stated (unless it’s the same from both ends). There is no “methyne” either, you need at least 2 carbons to triple bond together. Draw ethyne, and propyne now…

12. Ethyne and one triple bonded carbon pair, and as many hydrogen atoms that fit, JUST 2. This is NOT 1-propyne, because if the triple bond were on the right side, you’d just count carbons from that side (the end closest to the fancy part, here it’s a triple bond, is carbon #1. Just PROPYNE

13. 13

14. Let’s draw 1-butyne and 2 butyne next (put your triple bond in the right place!)

15. That’s 1-butyne above, counting from the right side. Right, left, who cares? Just keep track of the “first” carbon, it does not matter right or left. Below is 2 butyne The triple bond is between carbon #2 and #3, counting from EITHER direction.

16. Let’s draw some more… 1-decyne 1-pentyne 2-pentyne 3-hexyne

17. Let’s draw some more… 1-decyne 1-pentyne 2-pentyne 3-hexyne

18. Table P to count to 10 in Latin prefixes Table Q for hydrocarbons. 3 kinds of hydrocarbons (3 homologous series) contain ONLY Carbon + Hydrogen atoms Alkanes all C-C bonds are single, these are “saturated” hydrocarbons - they hold the MOST hydrogen atoms Alkenes Must contain only one C=C double bond, double bond must be enumerated unless too small to matter these are unsaturated hydrocarbons Alkynes Must contain only one CΞC triple bond, triple bond must be enumerated unless too small to matter these are also unsaturated hydrocarbons