Chemistry Helpers
Organic Chemistry

 

Organic Chemistry
·        Name given to the study of carbon and carbon compounds.
·        Living things contain many organic compounds. Products of living things, such as petroleum, wood and coal supply the raw materials from which organic chemicals are obtained.
 
I.                   Characteristics of Organic Compounds
A. Organic compounds are generally nonpolar  in nature. (symmetrical charge distribution)
B. Only a few are soluble  in water. (These include ethanoic acid, various sugars and some alcohols)
C. Organic compounds are generally nonelectrolytes; they do not ionize well and as a result are          poor conductors of electricity.
D.   Due to weak intermolecular forces of attractions, organic compounds usually have low melting points.
E.   Reaction rates of organic compounds tend to be slower than those of inorganic compounds. The bonding within the organic molecules itself (intramolecular as opposed to intermolecular forces) are covalent and very strongly held together.
 
II.                Bonding:
A. Carbon has 4 valence electrons. Due to the hybridization of these valence sublevels, carbon has 4 sites for bonds, forming a tetrahedral structure.
B.   Structural formulas are often used to represent the molecule:
Ex: Methane   CH4
 
 
C.   Isomers: compounds with the same molecular formula, but different structures, thus different properties                               
Ex: C5H12
 
 
 
 
 
D.   Carbon can bond with a second carbon by sharing
1 pair(s) of electrons (single bond)
2 pair(s) of electrons (double bond)
3 pair(s) of electrons (triple bond)
 
 
 
 
 
III.             Hydrocarbons: organic compounds containing only hydrogen and carbon
A.  Homologous Series:       a group of organic compounds with similar properties and related structures (each successive number increases by 1 carbon and 2 hydrogens)
 
                                                          Table Q
Alkanes:     CnH2n+2                         Alkynes:    CnH2n-2                          
Alkenes:     CnH2n                             Benzenes:           CnH2n-6                
1.    To name these compounds, you use prefixes dependents upon the number of carbons present in the substance.   Table P
 
          B. Aliphatic Compounds (Compounds that are aligned in a straight chain)
1.    Alkanes: CnH2n+2
All C to C bonds are single. This compound is said to be saturated (it has the maximum number of hydrogens around each carbon possible)              
To name alkanes: Use the prefix + -ane
# of carbons                 name                   molecular formula                  structural formula
1                           methane     CH4                               
2                           ethane
 
2.    Alkenes: CnH2n
Hydrocarbons containing one double carbon to carbon bond. Because of the double bond they are said to be unsaturated (they have less hydrogen atoms than do saturated compounds with the same number of carbons) *Cannot have a 1 carbon alkene*
To name alkenes: use prefix + -ene
# of carbons                 name                   molecular formula                  structural formula
1                           *cannot have – you need 2 carbons for the double bond                               
2                           ethene        C2H4
 
·              If the double bond is not on an end carbon, the name of the alkene will change as follows:
Number the carbons from the end of each side…then use the smallest number to tell where the double bond is located.
 
 
 
 
 
 
 
 
3.    Alkynes: CnH2n-2
.unsaturated hydrocarbons with one triple carbon to carbon bond.
To name alkynes: use the prefix + -yne
# of carbons                 name                   molecular formula                  structural formula
1                           *cannot have – you need 2 carbons for the triple bond                                  
2                           ethyne
 
·              If the triple bond is not on an end carbon, the name of the alkyne will change as follows:
Number the carbons from the end of each side…then use the smallest number to tell where the triple bond is located.
 
 
 
 
C.   Aromatic Hydrocarbons: closed chain (ring chain) structures that are often unsaturated with alternating double and single bonds.
 
1.    The Benzene Family: CnH2n-6
*you should know the following two*
 
a.     Benzene: C6H6
 
 
 
 
 
b.    Toluene: C7H8
 
 
 
 
 
 
IV.            Other Organic Compounds:
A.   Organic Alcohols: General Formula   R-OH                 
1.Monohydroxyl alcohol:
         a. contains one -OH group(s)
b. to name: use alkane name, drop the e and add –ol
c.     most alcohols are monohydroxyl
 
Example:             Structure              Molecular Formula                 Name
 
 
 
1a. Primary Alcohol:     one with the –OH group attached to an end carbon (attached to a carbon that is attached to only one other carbon)
ex:
 
 
1b. Secondary Alcohol:         one with the –OH group attached to a carbon that is attached to two other carbons
ex:
 
 
To name a secondary alcohol, you must name the longest carbon chain and everything that is attached to that chain is named as you would name the alkenes and alkynes.
          Ex:
1c. Tertiary Alcohol:     one with the –Oh group attached to a carbon that is attached to three other carbons.
Ex:
 
 
 
*name the same way you would name secondary alcohols!
 
 
2.    Dihydroxyl Alcohols:
a. contains      two    -OH group(s)
b. to name: use alkane name, drop the e and add –diol *also include the carbon #’s the –OH groups are attached to.
 
 
         
3.    Trihydroxyl Alcohols
a. contains      three -OH group(s)
b. to name: use alkane name, drop the e and add –triol *also, name the carbon #’s the –OH groups are attached to.
   
B.   Organic Acids (Carboxylic Acids) *weak electrolytes*
·        The only organic electrolytes
1.    General Formula:       R-COOH or R-C-O-H                    
a.     to name: use alkane name, drop the e and add –oic acid
 
Molecular Formula                 Structure              Name
          1
 
 
 
          2
 
 
 
 
C.   Aldehydes:
1.    General Formula   R-CHO or R-C-H         
a. to name: use the alkane name, drop the e and add -al
 
Molecular Formula                 Structure              Name
          1
 
 
 
          2
 
 
 
**be careful, name is close to alcohol name!!!
         
D.   Ketones:
1.    General Formula   R-C-R                           
a. to name: use the alkane name, drop the e and add –one, also name the # of the carbon containing the =O
Molecular Formula                 Structure              Name
         
 
 
 
E.   Esters: The product of a combination reaction between an acid and an alcohol.
1.    General Formula   R-COOR’                     
a. to name: use the beginning of the alcohol name and the ending of the acid name. Change the acid name by dropping –ic and adding    –ate.
 
Molecular Formula                 Structure              Name
         
 
 
 
 
F.    Ethers:
1.    General Formula   R-O-R’                                                      
a. to name: name the groups attached to the –O-
Molecular Formula                 Structure              Name
         
 
 
 
*Diethyl ether is commonly used as a solvent and anesthetic*
 
G. Halides: alkanes with halogens attached, either by addition or substitution    reactions.
1.    General Formula   R-X where X is any halogen 
a. to name: use the carbon # the halogen is attached to, then the prefix of the halogen, then the alkane (or alkene) name.
Halogen Prefixes:              F       fluoro
                                  Cl      chloro
                                  Br      bromo
                                  I        iodo
Molecular Formula            Structure              Name
 
 
 
H.   Amines:
1.    General Formula   R-NH2; functional group –NH2       
a. to name: drop the e off the alkane name, add -amine
 
Molecular Formula            Structure              Name
 
I.       Amino Acids: the building blocks of proteins, they are the combination of acids and amines.
 
1. Simple amino acids are named using the IUPAC system, but most are complex and common names are used.
 
Example:
 
 
 
 
J.     Amides: the combination of an amine and an aldehyde
 
1.    General Formula   R-C-NH2                                
a. to name: drop the e from the alkane name and add -amide
 
Molecular Formula            Structure              Name
 
 
 
 
 
V.               Organic Reactions:
·        Generally very slow in nature
·        Usually only the functional group is involved
 
A.   Substitution Reactions: only saturated hydrocarbons undergo substitution reactions.
Process by which         a hydrogen on an alkane is replaced by another substance (usually a halogen)                                                                           
          Start with 2 reactants                                                    end with 2 products
          (alkane + something)
Example:
 
 
 
B.   Addition Reactions: only unsaturated hydrocarbons undergo addition reactions.
Process by which         an alkene or alkyne react with something (such as a halogen) to break the double or triple bond and add a substance on.
          Start with 2 reactants                       end with 1 product
          (alkene/alkyne + something)
Remember how to name the products of substitution and addition reactions, these are your Halides.
Examples:
 
 
 
 
 
C.   Fermentation:
Process by which enzymes (usually produced in living organisms) catalyze the breakdown of large organic molecules to produce alcohol and carbon dioxide.                                                              
*usually yeast is involved, the enzymes produced by these yeasts act as a catalyst for the breakdown of organic molecules.
 
          Example:
.
 
 
 
D.   Esterification:
Process by which an organic acid and alcohol react to produce an ester and water  
*dehydration synthesis
*condensation reactions                                             
 
Organic acid                 +       alcohol                 =       ester           +       water
 
 
 
 
 
 
 
E.   Saponification:
Process by which         fats are hydrolyzed by strong bases to produce soap and glycerol                           
          Example:
 
 
F.    Polymerization:
Process by which a larger molecule (polymer) is made from smaller, repeating units.
Polymer:    a compound with a high molecular mass made up of smaller subunits (monomers) that have been bonded together.                       
          Types of polymers:
                   Natural: proteins, starch, cellulose
Synthetic: polyester, polyurethane, plastics, rubber, nylon, styrofoam
General Reaction:
nC2H4 = (-C2H4-)n
 
Types of Polymerization Reactions:
1.    Condensation polymerization:        releases water
2.    Addition polymerization:        breaks double or triple bonds
 
G. Oxidation by Aldehydes:
Process by which an aldehyde reacts with oxygen to produce an acid                                                                  
          Example:
 
 
 
 
 
H.   Combustion:
Process by which saturated hydrocarbons react with oxygen (are burned) to produce carbon dioxide, water and heat.                                                          
*usually considered the burning of fossil fuels
 


Write Your Questions Below



reaction of an acid with litmus paper,metal,base and phenolphthalein
March 18, 2014

Hello, please ask a specific question. Are you interested in acid base indicators? If so please look at Reference Table M. Are you interested in how acids and bases are made or named? If so please look at the topic Acids Bases.

Feel free to submit any questions that you may have. 

March 22, 2014 -  Replied By Expert

I am supposed to do an experiment to investigate a factor that affects the change in temperature when a salt is dissolved in water to produce an endothermic reaction. Please help with this because I am very confused about it all, eg where to start, what could the factor be
December 8, 2013

 Hi Mariam, what you are referring to is colligative properties. Boiling point elevation and freezing point depression. When a substance is dissolved in water it will cause the boiling point to rise, conversely it will cause the freezing point to decrease. This is why salt is used on icy walks - it causes the freezing point to drop (causes the ice to melt).

January 9, 2014 -  Replied By Expert

 
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