ALKANES POWERPOINT BY: HELEN LIN

WHAT ARE ALKANES? Alkanes are a series of hydrocarbons bonded with single bonds. Alkanes use the formula C 2 H 2n+2 The simplest form of an alkane is methane, CH 4

ALKANES An alkane, also called a paraffin, is a saturated hydrocarbon. Alkanes are hydrocarbons because they are only made up of 2 elements, hydrogen and carbon. The two main commercial sources of alkanes are petroleum(crude oil) and natural gases.

ALKANE STRUCTURE Alkane structures are centered around carbon and hydrogen bonds. Carbon wants four bonds so alkanes have a tetrahedral structure. Carbon is capable of catenation, which enables carbon to form a covalent bonds with itself.

FORMS OF ALKANES The first four alkanes (methane, ethane, propane, and butane) are all gases at room temperature, but the straight chain alkanes (alkanes with 5-16 carbons) are liquid at room temperature (gasoline, kerosene, motor oils, etc.), alkanes that are solids at room temperature start with C 17 H 36

COMBUSTION When an alkane has a complete combustion, it produces water and carbon dioxide. Alkanes only combust completely when there is enough oxygen available to allow it to do so. If there isn’t enough oxygen, it results in an incomplete combustion, and creates water and carbon monoxide.

SOLUBILITY Alkanes are insoluble in water but can be dissolved in organic matter. When alkanes are dissolved in a solvent, existing Van der Waals forces are being broken down and replaced by other Van der Waals forces. Liquid alkanes are good solvents for other covalent compounds.

PREFIXES/SUFFIXES Prefixes for alkanes are based on the number of carbons each gas contains. In numerical order the prefixes are: meth, eth, prop, but, pent, hex, hept, oct, non, dec, unde, dode, etc. All alkanes end with the suffix –ane.

ISOMERISM Structural isomerism is possible in all alkanes with four or more carbons. Structural isomerism means that there are two or more ways to draw out the structure of an alkane. For example: C 4 H 10 can either be butane or 2-methylpropane Butane 2-methylpropane

CYCLOALKANES Cycloalkanes follow the same rules as regular alkanes. Just like alkanes, cycloalkanes are made up of carbon and hydrogen and have only one bond, but the carbons in a cycloalkane form a ring. The simplest cycloalkane is cyclopropane.

CYCLOALKANES While cycloalkanes follow the same rules as alkanes, it no longer fits under the C 2 H 2n+2 formula. Cycloalkanes don’t fit under the formula because to be able to join carbons in a ring, two hydrogens have to be gotten rid of.

QUIZ a. One b. Two c. Three d. Four a. C 2 H 2n+2 b. C 2 H 2n c. C 2 H 3n+2 d. C 3 H 2n+2 a. CH b. HC c. HCl d. CH 4 a. Calcium and hydrogen b. Carbon and hydrogen c. Carbon and helium d. Calcium and helium a. carbon atoms b. helium atoms c. hydrogen atoms d. calcium atoms 1. How many bonds do alkanes have? 2. What is the formula for alkanes? 3. What is the simplest alkane structure? 4. What is gotten rid of in order to form a cycloalkane? 5. What are alkanes made up of?

VIDEO

WORKS CITED "Alkanes." Georgia State University, n.d. Web. 27 Apr "History." Physical Properties. Chemical Education Digital Library, n.d. Web. 26 Apr "Alkanes & Cycloalkanes." Alkanes & Cycloalkanes. Michigan State University, n.d. Web. 28 Apr "Hydrocarbon - Alkanes." Carbon, Atoms, Molecules, and Methane. Net Industries, Web. 27 Apr O'Leary, Donal. "Alkanes." Alkanes. Hypertext, n.d. Web. 29 Apr