Week # 2 - Alkanes and AlkenesLecture # 4 - AlkanesConcepts: Alkane root and ring names, alkane branch namesBoiling Point TrendsReaction Summary: Write the general reactions in words.Combustion:Ques. 1: Give the root names for all of the alkanes from one to 10 carbons.Ques. 2: a. Give the branch names for carbons one to four.b. What is the structure of the special branch called "isopropyl"?Ques. 3. What are the ring structures and names for carbons three to six?Ques 4. Write the IUPAC names for the following: Ques. 5. What is the general rule for melting and boiling points for a series of alkanes which increase in the number of carbons?Ques. 6. Which compound would have the lowest boiling point? Write out the structures.a) heptane or pentaneb) pentane or cyclopentanec) 2-methylbutante or pentaned) Which compound in each (a,b,c) has the strongest intermolecular forces of attraction? Explain why.Ques. 7. What is most significant about the saturated hydrocarbon portion of a molecule during a chemical reaction?Ques. 8: What is the combustion reaction of oxygen with butane? (Cigarette lighter)Ques. 9. What is the IUPAC name of each of the following:Ques. 10. What is the IUPAC name of each of the following:Compounds in Gasolinehttp://www.elmhurst.edu/~chm/vchembook/515gasolinefs.htmlGasoline is a complex mixture of over 500 hydrocarbons that may have between 5 to 12 carbons. Alkanes type compounds, either straight chain or branched compounds are present is greatest amounts. Smaller amounts of alkane cyclic and aromatic compounds are present. Very small or trace amounts of alkenes are present in gasoline. A few examples are given here. Self Quiz on gasoline compounds. http://www.elmhurst.edu/~chm/vchembook/515gasolinecpdQUIZ.html Compound Octane Boiling Ques. 11: Write the StructuresNumber Point Paraffins or Alkanes n-butane 113 -0.5n-pentane 62 36n-hexane 19 69 n-heptane 0 982-methylbutane 99 282,2-dimethylpropane 100 102,2-dimethylbutane 892,2-dimethylpentane 892,2,3-trimethylbutane 113 2,2,4-trimethylpentane 100 (isooctane) Olefins or Alkenes 1-pentene 152 2-methyl-2-butene 176 3-methyl-2-pentene 130 2,4,4-trimethyl-1-pentene164 Cycloalkanes or Naphthenes Cyclopentane 141 49 Methylcyclopentane 107 Cyclohexane 1101,2-dimethylcyclohexane 104 1,4-dimethylcyclohexane 66 AromaticsBenzene 99Toluene or methylbenzene 124 m-xylene or 1,3-dimethylbenzene 145 Ethylbenzene 124Propylbenzene 127Isopropylbenzene 132What is the octane number?http://www.elmhurst.edu/~chm/vchembook/514gasoline.htmlFuel octane requirements for gasoline engines vary with the compression ratio of the engine. Engine compression ratio is the relative volume of a cylinder from the bottom most position of the piston's stroke to the top most position of the piston's stroke. The higher an engine's compression ratio, the greater the amount of heat generated in the cylinder during the compression stroke.If fuel octane is too low for a given compression ratio, the fuel prematurely and spontaneously ignites too early and the fuel charge EXPLODES rather than BURNS resulting in incomplete combustion. The net effect is a loss in power, possible engine damage, and an audible "knock" or "ping", referred to as detonation. The octane number of gasoline is a measure of its resistance to knock.. The octane number is determined by comparing the characteristics of a gasoline to isooctane (2,2,4-trimethylpentane), and heptane. Isooctane is assigned an octane number of 100. It is a highly branched compound that burns smoothly, with little knock.. On the other hand, heptane, a straight chain, unbranched molecule is given an octane rating of zero because of its bad knocking properties. Straight-run gasoline (directly from the refinery distillation column) has an octane number of about 70. In other words, straight-run gasoline has the same knocking properties as a mixture of 70% isooctane and 30% heptane. Many of these compounds are straight chain alkanes. Cracking, isomerization, and other refining processes can be used to increase the octane rating of gasoline to about 90. Anti-knock agents may be added to further increase the octane rating. See table above for octane ratings of the compounds in gasoline.Ques. 12: Octane rating versus type of compound:Octane ratings ___?___ with increasing carbon chain length.Octane ratings ___?___ with carbon chain branching.Octane ratings increase in aromatics with same number of carbons. What octane gasoline should you purchase?For most automobiles, use the lowest grade of 87 octane, unless they specifically say to use a higher octane gasoline. Using higher octane grades does not provide any extra power or extra mileage.Boiling points and structures of hydrocarbons:http://www.elmhurst.edu/~chm/vchembook/501hcboilingpts.htmlThe boiling points of organic compounds can give important clues to other physical properties and structural characteristics. A liquid boils when its vapor pressure is equal to the atmospheric pressure. Vapor pressure is determined by the kinetic energy of molecules. Kinetic energy is related to temperature and the mass and velocity of the molecules (K.E. = 1/2 mv2). When the temperature reaches the boilingpoint, the average kinetic energy of the liquid particles is sufficient to overcome the forces of attraction that hold molecules in the liquid state.Vapor pressure is caused by an equilibrium between molecules in the gaseous state and molecules in the liquid state. When molecules in the liquid state have sufficient kinetic energy they may escape from the liquid and turn into a gas. Molecules with the most independence in individual motions achieve sufficientkinetic energy (velocities) to escape as gases at lower temperatures. The vapor pressure will be higher (more gas molecules are present) and therefore the compound will boil at a lower temperature.Boiling point principle:Molecules which strongly interact or bond with each other through a variety of intermolecular forces can not move easily or rapidly and therefore, do not achieve the kinetic energy necessary to escape the liquid state. Therefore, molecules with strong intermolecular forces will have higher boiling points. This is a consequence of the increased kinetic energy needed to break the intermolecular bonds so that individual molecules may escape the liquid as gases. The boiling point can be a rough measure of the amount of energy necessary to separate a liquid molecule from its