Tyna L. Meeks Unit 8: Organic Chemistry

Unit 10: Organic Chemistry Organic Chemisty – Study of carbon and most carbon compounds. Stems to a time when it was believed that carbon compounds could only be made by living things, or organisms

Unit 10: Organic Chemistry Carbon Bonding If an atom cannot lose or gain, and decides to SHARE its electrons instead a unique bond is formed… COVALENT bond Sharing equally is NONPOLAR Sharing equally is NONPOLAR Sharing unequally is POLAR Sharing unequally is POLAR

Unit 10: Organic Chemistry Remember: COVALENT bonds cause MOLECULAR SUBSTANCES that exhibit the following physical properties: low melting point low boiling point poor conductor of heat and electricity generally nonpolar, so they dissolve in nonpolar solvents

Unit 10: Organic Chemistry Carbon Bonding sharing of 1 pair of electrons creates a single bond sharing of 1 pair of electrons creates a single bond sharing of 2 pairs of electrons creates a double bond sharing of 2 pairs of electrons creates a double bond sharing of 3 pairs of electrons creates a triple bond sharing of 3 pairs of electrons creates a triple bond

Unit 10: Organic Chemistry Lewis Dot Structures: HOrganic molecules HOrganic molecules H C Halways forms the Hfour bonds around carbon!! Hfour bonds around carbon!!

Unit 10: Organic Chemistry The four bonds around carbon can be arranged as: 4 single bonds 4 single bonds 2 single bonds and a double bond 2 single bonds and a double bond 2 double bonds 2 double bonds 1 single bond and a triple bond 1 single bond and a triple bond

Unit 10: Organic Chemistry The four bonds around carbon can be arranged as: 4 single bonds - tetrahedral 4 single bonds - tetrahedral 2 single bonds and 2 single bonds and a double bond – trigonal planar a double bond – trigonal planar 2 double bonds - linear 2 double bonds - linear 1 single bond and 1 single bond and a triple bond - linear a triple bond - linear

Unit 10: Organic Chemistry Organic molecules can be represented several ways: molecular formulas: C 3 H 8 molecular formulas: C 3 H 8 structural formulas:

Unit 10: Organic Chemistry Saturated- single bonds: all carbons have as many groups as possible Alkanes - single bonds only between all carbons Alkanes - single bonds only between all carbons

Unit 10: Organic Chemistry Unsaturated- double or triple bonds: bonds can be broken to allow for the addition of more atoms Alkenes - double bond between two carbons Alkenes - double bond between two carbons Alkynes – triple bond between two carbons Alkynes – triple bond between two carbons

Unit 10: Organic Chemistry All organic molecules that have the same type of bonding are called homologous series and can be identified by simple formulas: Table Q Table Q Alkanes - C n H 2n+2 Alkenes - C n H 2n Alkynes - C n H 2n-2

Unit 10: Organic Chemistry Learning to name our organic molecules: Remember our single, double, and triple bonds - Alkanes – has suffix -ane Alkenes – has suffix -ene Alynes – has suffix -yne

Unit 10: Organic Chemistry Learning to name our organic molecules: Prefixes for the names come from the number of carbon atoms found in molecule: Table P 1 - meth4 - but7 - hept 2 - eth5 - pent8 - oct 3 - prop6 - hex9 – non 10 - dec

Unit 10: Organic Chemistry Learning to name our organic molecules: Naming was based on commonalities, but a universal naming system has been established called the IUPAC system.

Unit 10: Organic Chemistry IUPAC Naming System Rule 1- The longest unbranched carbon chain is called the parent chain, or parent alkane. Rule 2- The carbon atoms in the longest chain are numbered.

Unit 10: Organic Chemistry IUPAC Naming System Rule 3- The group or the alkyl group is identified by the number of the carbon it is attached to. **Alkyl group- an alkane chain attached to a carbon in the parent chain, identify the number of carbons in the chain itself, use the prefix and add -yl

Unit 10: Organic Chemistry IUPAC Naming System Rule 4- The appropriate numerical prefix (di,tri, ) is used to indicate how many times the attached group appears. A carbon atom number must be used to indicate the position of each such group. If two of the same group are attached to the same carbon atom, the number of the carbon atom is repeated.

Unit 10: Organic Chemistry IUPAC Naming System Rule 5- The complete name of the compound is obtained by first naming the attach groups. Each attached group is located by the number of the carbon atom to which it is attached. The carbon number is the prefix.

Unit 10: Organic Chemistry IUPAC Naming System Rule 6- non akyl groups and halogens are named with locator numbers for their position on the carbon chain Rule 7- If there are two or more different substituted groups in a name, they are arranged with the halogens given fist, followed by alkyl groups, each in alphabetical order.

Unit 10: Organic Chemistry Organic molecules that have the same number of carbons and hydrogens, but are arranged differently are called isomers. Isomers don’t start until butane, and there are two ways to draw C 4 H 10 Isomers don’t start until butane, and there are two ways to draw C 4 H 10 H H H H H H C C C C H H C H H H H H H C C C H H H H H H C C C H H H H H H H

Unit 10: Organic Chemistry Isomers: Isomers have the same molecular formula but different structural formulas - due to these differences in their structure, they have different physical properties (boiling points and such) Isomers have the same molecular formula but different structural formulas - due to these differences in their structure, they have different physical properties (boiling points and such) It is the ability to form isomers that is largely responsible for the huge number of organic molecules. It is the ability to form isomers that is largely responsible for the huge number of organic molecules.

Unit 10: Organic Chemistry Learning to name our organic molecules: Some molecules are circular, or cycloalkanes. A very special case of these are known as AROMATICS

Unit 10: Table R

Organic Molecules Containing Halides When any of the halogens replaces a hydrogen atom in an alkane, it is called an organic halides, or halocarbon F, Cl, Br, or I

Unit 10: Table R Organic Molecules Containing Oxygen Alcohols (ol) have the hydroxyl group –OH Primary alcohol – has an OH attached to a carbon which is attached to only one other carbon Secondary alcohol - has an OH attached to a carbon which is attached to two other carbons Tertiary alcohol - has an OH attached to a carbon which is attached to three other carbons

Unit 10: Table R Organic Molecules Containing Oxygen Alcohols (ol) have the hydroxyl group –OH Monhydroxy alcohol – an alcohol with only one OH Attached Dihydroxy alcohol - an alcohol with two OH’s Attached Trihydroxy alcohol - an alcohol with three OH’s attached

Unit 10: Table R Organic Molecules Containing Oxygen Aldehyde (al)- has a carbonyl group at the end of a hydrocarbon chain. R-CHO Ketone- has a carbonyl group on the interior of a hydrocarbon chain. R-COR`

Unit 10: Table R Organic Molecules Containing Oxygen Carboxylic acids contain the carboxyl group (oic). –COOH

Unit 10: Table R Organic Molecules Containing Oxygen Ethers contain an oxygen atom that is bonded to two carbon atoms. R-O-R` general formula Ethers are formed by the combination of two primary alcohols through dehydration

Unit 10: Table R Organic Molecules Containing Oxygen Esters contain an oxygen atom that is bonded to two carbon atoms AND a double bonded oxygen on the second group R-O-OR` general formula Esters are formed by the combination of a primary alcohol and a carboxylic acid through dehydration

Unit 10: Table R Organic Molecules Containing Nitrogen Amines are created when the addition of a -NH 2 to the carbon chain takes place

Unit 10: Table R Organic Molecules Containing Nitrogen Amides are created when the addition of a -NH 2 to the carbon chain takes place next to a double bonded oxygen

Unit 10: Table R Organic Molecules Containing Nitrogen Amino Acids:

Unit 10: Table R Organic Molecules Containing Nitrogen Peptide Bonds are created when two amino acids bond together Long chains of amino acids create peptides, and eventually, proteins…

Unit 10: Organic Reactions Combustion C x H y + O 2  CO 2 + H 2 O + energy This burning of fuels always releases energy (EXOTHERMIC), and the amount of energy released can be easily calculated:

Unit 10: Organic Reactions Substitution: ASS alkanes undergo substitution ONLY - substitute in a halogen (Group 17) - break off 1 OR MORE hydrogens and put the halogen in its place, the hydrogens will reappear in another molecule on the product side

Unit 10: Organic Reactions Addition: double or triple bond present! -break the multiple bond and add two things, one on each side of the multiple bond

Unit 10: Organic Reactions Esterification: creation of an ester Take an organic acid AND a primary alcohol DEHYDRATE (remove water)

Unit 10: Organic Reactions Saponification: breaking down an ester Ester + base  alcohol + soap

Unit 10: Organic Reactions Fermentation: make alcohol from sugar

Unit 10: Organic Reactions Organic Reaction: Polymerization: creating long chains of molecules -addition polymerization -condensation polymerization

Unit 10: Organic Reactions Condensation Polymers The oxygen bearing organics can be made into chains as well by removing an OH from one molecule and an H from another to form WATER CONDENSATION

Unit 10: Organic Chemistry Ethanol has been made since ancient times by the fermentation of sugars. All beverage ethanol and more than half of industrial ethanol is still made by this process. Simple sugars are the raw material. Zymase, an enzyme from yeast, changes the simple sugars into ethanol and carbon dioxide. The fermentation reaction, represented by the equation below: C 6 H 12 O 6  2CH 3 CH 2 OH + ___CO 2 a.Draw the structural formula of ethanol b.Balance the equation above

Unit 10: Organic Chemistry 2-butanone is a manufactured chemical but it is also present in the environment from natural sources. Nearly half of its use is in paints and petroleum based coatings because it will quickly evaporate into the air and it dissolves many substances. It is made by some trees and found in some fruits and vegetables in small amounts. It is also released to the air from car and truck exhausts. a. Draw the structural formula of 2-butanone b. Determine the molar mass for this molecule c. 2-butanone can dissolve or be dissolved by both polar and nonpolar substances. Name a nonpolar liquid mentioned above. d. Should 2-butanone be considered environmentally safe?

Unit 10: Organic Chemistry Ethanol is an organic compound, most important of the alcohols, chemical formula CH 3 CH 2 OH. Produced by fermentation, it is the intoxicating ingredient in alcoholic beverages. Ethanol has many uses as a solvent, raw material, extraction medium, antifreeze, antiseptic, and gasoline additive and substitute. Butane C 4 H 10, gaseous, a hydrocarbon that is obtained from natural gas or by refining petroleum. It can be liquefied at room temperature by compression. There are two structural formulas of butane. a. Draw the two isomers of butane b. Explain in terms of intermolecular forces why ethanol has a much higher boiling point than butane.

Unit 10: Organic Chemistry Gasoline is a mixture of hydrocarbons, one of which is octane. Sometimes water gets into the fuel tank of the automobile. Because it can not mix with the gasoline, it sinks to the bottom of the fuel tank. In cold weather the water can sometimes freeze in the gas lines and interrupt the flow of gasoline to the engine. An additive that contains the alcohol, methanol, can be added to the fuel tank that prevents the freezing of water by forming a solution with water that won’t freeze a. Draw the structural formula of the gasoline component, octane b. Draw the structural formula of the gasoline additive, methanol c. Explain why the water can dissolve in the alcohol, but not dissolve with the gasoline.

Unit 10: Organic Chemistry 1. Draw the structural formula for ethyl acetate. (the correct IUPAC name is ethyl ethanoate 2. What is the chemical name for the alcohol that reacts with ethanoic acid to produce ethyl ethanoate? 3. Draw a correct structural formula for dichloromethane 4. To what class of organic compounds does dichloromethane belong?