GO 1: You Will Explore Organic Compounds As a Common Form of Matter

Organic chemistry:

GO 1: You will explore organic compounds as a common form of matter

GO 2: You will describe chemical reactions of organic compounds

Lesson 1: Intro

• You will define organic compounds as compounds containing carbon, recognizing inorganic exceptions such as carbonates, cyanides, carbides and oxides of carbon
• You will identify and describe significant organic compounds in daily life, demonstrating generalized knowledge of their origins and applications; e.g., methane, methanol, ethane, ethanol, ethanoic acid, propane, benzene, octane, glucose, polyethylene

Organic compound include all compounds of carbon except:

a) Oxides (CO2, CO)no hydrogen

b) Carbonates (Na2CO3)

c) Carbides (K4C)Ionic

d) Cyanides (LiCN)

They have to consist of primarily carbon and hydrogen (hydrocarbon).

The carbon molecule has 4 valence electrons.

It does not generally form ionic bonds because of its number of valence electrons. It forms covalent bonds to non-metal atoms like hydrogen, oxygen and halogens.

Organics are derived from:

a) Living organisms

1. Food (protein, fats, carbohydrates)
2. Fuels (methane, ethane)
3. Fabrics (cotton, wool, rayon)
4. Wood and paper products
5. Antibiotics and vitamins
6. Flavours and perfumes
7. Explosives

b) Synthetics

1. Paint, varnish
2. Plastics
3. Soap/detergent
4. Chemical additives (pesticide, insecticide, fertilizer)

Hydrocarbons

AliphaticsCyclicsAromatics

Alkanes Alkenes Alkynes(Benzene parent)

Nelson Read pg 356-358

Do pg 361#1,2

• You will name and draw structural, condensed structural and line diagrams and formulas, using International Union of Pure and Applied Chemistry (IUPAC) nomenclature guidelines, for saturated and unsaturated aliphatic (including cyclic) and aromatic carbon compounds containing up to 10 carbon atoms in the parent chain (e.g., pentane; 3-ethyl-2,4- dimethylpentane) or cyclic structure (e.g., cyclopentane)

Lesson 2: AlkanesCnH2n+2 (empirical/molecular formula)

-simplest organic molecule

-saturated – contain only single covalent bonds which means each carbon has 4 bonds making a tetrahedral shape around it.

A continuous chain alkane has the carbon atoms all in a straight chain. They are named according to the root words below with the ending ‘ane’. (IUPAC naming system)

-root words

Eg.

-naming branched chain alkanes:

Alkanes can have hydrocarbon branches called alkyl groups. The alkyl groups are named first and use the same root name but with a ‘yl’ ending. Eg. Methyl, ethyl, propyl, butyl, etc.

Use the following steps to name branched chain alkanes:

1. Find the longest continuous chain of carbons in the molecule.

2. Number the carbons in the main chain in sequence.

Start at the end that will give the alkyl groups the smallest numbers. The numbers will be the ‘address’ of the alkyl group.

3. Prefixes are used to indicate how often an alkyl group appears (if it appears more than once). Prefixes: di, tri, tetra, penta are used.

4. Alkyl groups are listed in alphabetical order (ignoring the prefixes)

5. Start the name with the address of the alkyl group and then the name of it, continue this with the next alkyl group, lastly the main chain is named as per usual.

-commas separate numbers

-hyphens separate a number from a word

The name is considered one word with no upper-case letters.

Nelson summary pg 368

Questions pg 373 #6,7ab

-writing structural formula

1. Find the parent carbon chain (main chain) at the end of the name and draw its structure leaving the hydrogen’s off.

2. Number the carbons in this parent chain.

3. Identify the substituent (branch, or also called alkyl) groups and draw them attached to the proper parent carbon (by address).

4. Add hydrogen’s to fill in the rest of the bonding sites.

Nelson summary pg 369

Questions page 370 #7, 9-11 pg 373 #5,8

-other types of structural formulas

Condensed Structural Formulas: Leave out some of the bonds (C-H) from the structural formula. Eg. Butane CH3-CH2-CH2-CH3

Line Structural Formulas: the most condensed type of formula. A change in direction of the line indicates a carbon position. Each line therefore indicates a carbon-carbon bond. No other bonds or atoms are shown unless they are something other than carbon and hydrogen.

pg 373 #7c

-Properties of Alkanes:

Alkanes contain only covalent bonding without any major difference in polarity (no dipoles). Therefore the only type of intermolecular bonding that exists is London dispersion. The larger the molecule the more London dispersion force and therefore the more likely it will be a condensed state (liquid or solid). Since there is very little intermolecular bonding (compared to some other molecules) the smaller alkanes are gases at SATP.

Pg 375 table 5

Another result of being non-polar is that they are insoluble in water. Water is very polar and ‘like dissolves like’ therefore alkanes are soluble in other organic (or non-polar) solvents but NOT polar substances like water.

Homologous series- same functional group (general structure) but differ in their length.

You need to be able to describe how properties change within a homologous series.

Nelson q pg 373 #6,7,10

Lesson 3: Cycloalkanes, Alkenes and Alkynes

Cycloalkanes and AlkenesCnH2n

Cycloalkanes: If a hydrogen is removed off of each end of an alkane, the ends can be joined to make a cycloalkane. It consists of all single bonded carbons in a ring. (saturated!!) These too can be branched.

Naming them is similar to alkanes except the root name has the prefix ‘cyclo’ in front of it. The branches still have the lowest ‘address’ or number to them, and with a ring format, one of the branches will always have the number ‘1’.

Eg.

Properties: - higher b.p. and density than corresponding alkane (more compact)

-small ones are more reactive because of restrictive bond angles (C3-5)

Nelsonpg373#8

Alkenes: -have at least one double bond in them - unsaturated

This spot with the double bond is inflexible (rigid) and also unstable. This makes it more reactive (less stable) than its corresponding alkane.

Naming them is similar to alkanes except

-the longest (parent) chain MUST have the double bond(s) in it.

-the double bond also has to have an ‘address’ and takes priority over the branches therefore the double bond MUST have the lowest possible number when numbering the chain.

-the parent chain ends in the address-‘ene’.

-multiple double bonds need addresses and prefixes before the ‘ene’. Eg. but-1,3-diene

Exception: ethylene

The properties of alkenes are very similar to their corresponding alkane except that their boiling points are even slightly lower because of less atoms (electrons) and therefore less London dispersion than the alkane with the same # of carbons.

Eg.

*for each double bond or ring structure their empirical formula drops by two hydrogen

AlkynesCnH2n-2

-Organic compounds containing carbon-carbon triple bonds (unsaturated)

-Named with the same rules as alkenes but ending in ‘yne’.

Exception is also the two carbon structure which is called ‘acetylene’ instead of ethyne

Properties are similar to their corresponding alkanes and alkenes except that their boiling points are actually higher than their corresponding alkane. They have fewer electrons (less LD) but their rigid linear structure and nature of the triple bond cause them to attract one another more and therefore a tighter structure and higher boiling point are a result.

Nelson pg 377#1-7 (omit 6)

Lesson 4: Structural Isomers

• You will define structural isomerism as compounds having the same molecular formulas, but with different structural formulas, and relate the structures to variations in the properties of the isomers
• You will build molecular models depicting the structures of selected organic and inorganic compounds

A structural isomer has the same empirical chemical formula but a different structure (shape). It would therefore be named differently! The name and structure identifies the isomer.

The physical properties of structural isomers are different. The more highly branched the hydrocarbon is, the lower its boiling point compared with its structural isomers.

CnH2n+2(aliphatic alkane)

CnH2n (alkene or cyclic alkane)

CnH2n-2 (alkyne, double alkene, or combination of cyclic and alkene)

Eg. Draw structural isomers of C5H8.

Nelson pg 377#6, 380 #1-11

Assignment

Lesson 5: Aromatics

A special group of hydrocarbons compounds that are uniquely stable and flat in shape.

They are unsaturated and cyclic.

They are often made up of benzene or benzene derivatives.

They have pleasant odours (hence the name)

Benzene (C6H6); A six member carbon ring with a hydrogen attached to each carbon. (3 double bonds6x 1.5 bonds)

Derivatives of Benzene: Compounds containing substituents (branches) attached to the benzene ring. The benzene ring may be named as a branch or as the parent molecule depending on the amount of branching of each part of the molecule.

Nomenclature:

-benzene as a branch is called ‘phenyl’.

-benzene as the parent chain: one branch does not require an ‘address’ since it is always ‘one’ (as per cyclos).

-two branches – use numbers or an older system of ‘ortho’(1,2), ‘meta’(1,3), ‘para’(1,4) to show the branch positions.

eg.

Hydrocarbon Derivatives: contain a ‘functional group’ which is a chemically reactive part (this can include the double and triple bonds). The functional group gives specific characteristics to chemical reactions. Organic compounds are classified by functional groups.

• You will name and draw structural, condensed structural and line diagrams and formulas, using International Union of Pure and Applied Chemistry (IUPAC) nomenclature guidelines, for saturated and unsaturated aliphatic (including cyclic) and aromatic carbon compounds containing only one type of a functional group (with multiple bonds categorized as a functional group; e.g., pent-2-ene), including simple halogenated hydrocarbons (e.g., 2- chloropentane), alcohols (e.g., pentan-2-ol), carboxylic acids (e.g., pentanoic acid) and esters (e.g., methyl pentanoate), and with multiple occurrences of the functional group limited to halogens (e.g., 2-bromo-1-chloropentane) and alcohols (e.g., pentane-2,3-diol)
• You will identify types of compounds from the hydroxyl, carboxyl, ester linkage and halogen functional groups, given the structural formula
• You will compare, both within a homologous series and among compounds with different functional groups, the boiling points and solubility of examples of aliphatics, aromatics, alcohols and carboxylic acids

Here are some examples (the ones that we will study), but there are others.

*R represents any hydrocarbon chain/ring

Lesson 6: Halocarbons/Alkyl and Aryl(Aromatics) Halides

-result from the substitution of a halogen for hydrogen in a hydrocarbon. {If the hydrocarbon is an aliphatic chain, it may also be called an alkyl halide. If the hydrocarbon is attached to a benzene ring, it is called an aryl halide.}

Nomenclature:

-The halogen is treated just like a branch using the names

Fluorofor Fluorine

Chlorofor Chlorine

Bromofor Bromine

Iodo for Iodine

Eg.

Properties:

-they have a dipole because the halogen is very electronegative compared to the carbon. This means that the electrons sit closer to the halogen creating a partial separation of charge – dipole.

-the dipole in the molecule causes stronger intermolecular bonding (now has dipole-dipole in ADDITION to LD forces). This raises the boiling point compared to the molecule without the halogen.

- the dipole also makes the molecule more likely to react. (easier to remove the halogen than if it was a hydrogen).

-depending on the amount of the molecule that is polar (dipoles) compared to the amount that is non-polar, the molecule may or may not dissolve in polar solvents like water. (like dissolves like)

-many are toxic!!! Eg. CFC’s (chloro-fluoro- carbons) and PCB’s

1. addition reaction; halogenations

Halogenation is the ADDITION of a halogen to an alkene or alkyne. When a halogen reagent like chlorine (Cl2) or bromine (Br2) is added, the product is a disubstituted halocarbon.

Eg.

*Bromine is used as a saturation test for organic molecules. Bromine has a brown-orange color, but most organic compounds of bromine are colorless. Loss of the orange color when added to the organic molecule is a positive test for unsaturation (alkene or alkyne).

Also a hydrogen halide like hydrogen chloride or hydrogen bromide can be added to produce a monosubstituted halocarbon.

Eg. Addition of hydrogen chloride to ethene

2. substitution reaction(reactions of alkanes and aromatics)

Uses halogens like Cl2 or Br2 (slow process and is unpredictable as to where the halogen will end up or how many will end up on the molecule)

Eg.

Lesson 7: alcohols

Are organic compounds with a hydroxyl (-OH) group attached.

The oxygen atom is held tightly to the carbon atom, and the hydrogen atom is held tightly to the oxygen atom so the alcohol does not display acidic or basic properties even though an –OH group is present. These alcohols are non-ionic; the oxygen is covalently bonded to the carbon. Generally most alcohols are saturated.

Primary alcohol: The carbon with the alcohol has only one other carbon attached to it (end carbon).

Secondary alcohol: The carbon with the alcohol has two other carbons attached to it. (middle carbon)

Tertiary alcohol: The carbon with the alcohol is completely branched (3 other carbons attached to it.(middle and branched as well)

Nomenclature

IUPAC: (the hydroxyl is treated much like a double or triple bond)

-for continuous straight chain and substituted alcohols, drop the ‘e’ ending of the parent alkane name and add the ‘ol’ ending for the alcohol. The parent alkane is the longest continuous chain of carbons that includes the carbon with the hydroxyl group attached.

-number the longest chain giving the position of the hydroxyl group the lowest possible number.

-alcohols containing two, three and four hydroxyl branches are called diols, triols, and tetrols. (Don’t drop the ‘e’ on the parent name. Parent-addresses-prefix‘ol’)

Eg.

-compounds with more than one hydroxyl group are commonly called ‘glycols’.

Eg. Ethylene glycol

-hydroxyl named as a branch is ‘hydroxy’

Properties:

-have strong hydrogen bonding (makes alcohols a liquid)

-high boiling points

-low freezing points

-polar molecules – more soluble in water than other hydrocarbons we have seen yet.

Preparation of alcohols:

1. Hydration Reaction (Addition)

-add water to alkene or alkyne

2. Fermentation-the production of ethanol from sugars by the action of yeast or bacteria

GlucoseEthanol + carbon dioxide (do chemical formulas)

Ethanol is the intoxicating substance in alcoholic beverages. Fermentation can take place by distilling (removing water) to make hard alcohols or without distillation to form beer. Wine is higher alcohol content than beer because additional alcohol is added

Lesson 8:Carboxylic Acids (organic acids)

-compounds with a carboxyl group COOH

-they are weak acids since the H on the hydroxyl group slightly ionizes in solution to give an H+. Having two oxygen on the carbon makes the H in the carboxyl acidic even though the H in the hydroxyl of an alcohol is not.

Nomenclature:

-the ‘e’ ending of the parent alkane is replaced by the ending ‘oic acid’. An address is not necessary as it is always on the end (carbon 1) of the parent chain.

Eg.

Methanoic acid

Ethanoic acid

Propanoic acid

Oxalic acid

*Benzoic acid

2-hydroxybenzoic acid

Naming branches:

Eg.

Properties of Carboxylic acids:

-they have higher melting and boiling points than similar alkanes. This is due to their hydrogen bonding. Aromatic carboxylic acids are crystalline solids at room temperature

-small chain (1-4 carbons) are miscible with water (mix) since they are polar. The solubility drops with higher carboxylic acids as more of the molecule is non-polar than polar. (like alcohols). Most will still dissolve in organic polar solvents like acetone or ethanol

-smaller ones are colorless, volatile and have a sharp unpleasant odour

-higher mass aliphatic ones are non-volatile, have a low melting point and are waxy solids.

A fatty acid is a continuous chain carboxylic acid that was first isolated from fats.

Eg. Stearic acid is obtained from beef fat (C18). It is also used to make wax candles

-Reactions of carboxylic acids:

1. esterification (to form an ester)

alcohol + carboxylic acid - ester + H2O

• You will predict the ester formed from an alcohol and an organic acid

2. Neutralize a base

3. react with active metals (group 1 and 2) to form hydrogen gas. (acid reaction)

eg. Pg 438 Nelson

Lesson 9: Esters

-derivatives of carboxylic acids in which the OH of the carboxyl group has been replaced by an –O-R from an alcohol. (esterification)

The R group can be short or long chains, aliphatic (alkyl) or aromatic (aryl), saturated or unsaturated.