ET III Ch.14 Hydrocarbons

What is a hydrocarbon?

Simplest organic compounds containing only two elements, hydrogen and carbon

How are most hydrocarbons obtained?

from natural gas and petroleum by fractional distillation according to their boiling points

What are the boiling points of certain hydrocarbons are obtained from natural gas and petroleum by fractional distillation?

• <70⁰C: Petroleum ether

• 85-200⁰C: Gasoline

• 200-300⁰C: Kerosene

• 300⁰C: Lubricating oils

The physical state of hydrocarbons depends on the _______ of the carbon chain

length

C to C4 are _______

Gases

C5 to C17 are

Liquids

C18 and higher are _______

Solids

What are alkanes?

Carbons joined together with single bonds are alkanes

How are alkanes named?

named according to the number of carbon atoms in the chain and contain the suffix –ane

List the prefixes of alkanes according to the number of carbon atoms in the chain

1. Meth (one carbon)

2. Eth (two carbon)

3. Prop

4. But

5. Pent

6. Hex

7. Heat

8. Oct

9. Non

10. Dec

What is the type formula used to predict the number of hydrogens in any alkane, provided the number of carbons?

CnH2n+2

(N being the number of carbon atoms)

What are alkanes also called?

Saturated Hydrocarbons

What are Akyl groups?

When hydrogen atoms are removed from alkanes, the new structure is no longer a complete compound, but a group of atoms capable of attaching to another atom where a hydrogen used to be

What are Akyl groups?

When hydrogen atoms are removed from alkanes, the new structure is no longer a complete compound, but a group of atoms capable of attaching to another atom where a hydrogen used to be

what is the type formula for Akyl groups to predict the number of hydrogens they have?

CnH2n+1

(N is the amount of carbons)

How are Akyl groups named?

By replacing the –ane suffix with -yl

List some Alkanes and what they are as Akyl groups

Methane CH4 becomes methyl CH3

Ethane C2H6 becomes ethyl C2H5

Propane C3H8 becomes propyl C3H7

Butane C4H10 becomes butyl C4H9

Pentane C5H12 becomes pentyl C5H11

What are Alkyl halides?

Alkyl groups that attach to group 7a (halogens) on the periodic table

What is the type formula for Akyl halides to predict the amount of hydrogens?

CnH2n+1X

(N is the amount of carbons, X is the halide)

When does the simplest Akyl halide occur?

when a hydrogen atom in methane is replaced by chlorine, this is called methyl chloride (chloromethane)

Replacement of additional hydrogen atoms by chlorine atoms yields:

• Methylene chloride (dichloromethane)

• Chloroform (trichloromethane)

• Carbon tetrachloride (tetrachloromethane)

Match a photo of the structure for methyl chloride (chloromethane)

Match a photo of the structure of methylene chloride (dichloromethane)

Match a photo of the structure of chloroform (trichloromethane)

Match a photo of the structure of carbon tetrachloride (tetrachloromethane)

What is an isomer?

Two or more substances having the same molecular formula but different structural formulas

Isomers are a properly of what?

Alkanes that begin with butane

What does IUPAC stand for?

International Union of Pure and Applied Chemists

What is the International Union of Pure and Applied Chemists (IUPAC)?

A system that:

• Is used worldwide

• Allows chemists everywhere to communicate effectively

• Has three rules

What are the three rules of IUPAC?

1. Find longest carbon chain

2. Number the carbons

3. Locate and name any alkyl groups attached to the longest chain

What are Alkenes?

The simplest unsaturated hydrocarbons that contain one double bond in the chain

Multiple bonds present in a carbon chain are referred to as

unsaturated hydrocarbons

Alkenes contain

less hydrogen atoms than it could if only single bonds were present

What is the simplest alkene?

Ethene

Match a photo of the structure of Ethene

What is the type formula for Alkenes to predict the amount of hydrogens atoms?

CnH2n

What are Alkynes?

Another unsaturated hydrocarbon contains a triple bond between adjacent carbon atoms

What is the first member of the series of Alkynes?

Ethyne or Acetylene

Match a photo of the structure of ethyne or acetylene

What is the type formula for Alkynes to predict the number of hydrogens?

CnH2n-2

What are aromatic hydrocarbons?

Compounds classified as aromatic that contain a benzene ring, or a system of benzene rings

What are aromatic hydrocarbons also known as?

Arenes

How did aromatic hydrocarbons get their name?

The first ones found had pleasant odors (vanilla and oil of wintergreen)

What is the molecular formula of benzene?

C6H6

What is the structure for benzene?

Typically drawn with alternating double bonds between carbons, however the newest most correct form is with a circle in the middle to show the characteristic of resonance within benzene. The electrons are entirely “delocalized” evenly across all size carbon atoms.

What are the physical properties of benzene?

• At room temperature and 1 atm, benzene is a colorless liquid that is insoluble in water

• Extremely flammable

• Its use has been linked to certain blood disorders (some types of leukemia)

• Good organic solvent

• Starting material for the synthesis of many widely used compounds

  • Plastics, synthetic rubber, pharmaceuticals, pesticides…

What is a derivative of benzene?

When one hydrogen of benzene is replaced (Also called monosubstiuted benzenes)

List some derivative of benzene

• Toluene (methylbenzene, methyl group replaces a hydrogen)

• Phenol (hydroxybenzene, hydroxide replaces a hydrogen)

• Aniline (aminobenzene, NH2 replaces a hydrogen)

Describe toluene

• Named because it can be obtained from the bark of the South American tolu tree

• Extremely good solvent for other organic compounds such as paints and varnishes

• Frequently remembered as the starting material for the explosive trinitrotoluene (TNT)

Describe phenol

• Derivative of benzene containing one or more – OH groups

• Colorless, crystalline solids that are soluble in water and weakly acidic (pH 6), hence phenol’s other name carbolic acid

• Has been used as a general disinfectant since the 1860’s when it was discovered to be the active agent in German creosote (a deodorant in sewage treatment)

What is phenols other name?

Carbolic acid

Who was Joseph lister and what did he do?

English surgeon who hypothesized that phenol may have some value in stopping postoperative putrefactive infections

• Soaked gauze dressings in various concentrations of phenol and applied them to compound-fracture wounds of his surgical cases

• Infections dropped from over 50% to less than 2%