Presentation on theme: "Do Now Take out your worksheet (work in group first ) Objective Doing the problems from the worksheet (for going over the naming method) Saturated compounds."— Presentation transcript:
Do Now Take out your worksheet (work in group first ) Objective Doing the problems from the worksheet (for going over the naming method) Saturated compounds /Unsaturated compounds Comparison between Alkane ;Alkene ;Alkyne Isomers Homework P 719/43,44,45,48
Saturated compounds Concept : Organic compounds that contain the maximum number of hydrogen atoms per carbon atom Example : Alkanes Unsaturated compounds Concept : Compounds that contain double or triple carbon-carbon bonds Example : Alkenes ;Alkynes
Alkanes The only bonds in alkanes are single covalent bonds C n H 2n+2 Ethane Ethene Ethyne Alkenes Hydrocarbons that contain one or more carbon- carbon double covalent bonds C n H 2n Alkynes Hydrocarbons that contain one or more carbon- carbon triple covalent bonds. C n H 2n-2 Every bond means two atoms sharing two electrons together Guessing about bonds
NameMolecular structureBoiling point (Casers) C2C2 EthaneCH 3 --CH 3 -88.5 EtheneCH 2 == CH 2 -103.9 Ethyne-81.8 C3C3 PropaneCH 3 CH 2 CH 3 -42.0 PropeneCH3CH==CH2-47.0 Propyne-23.3 The introduction of a double or triple bond into a hydrocarbon does not have a dramatic effect on physical properties such as boiling point. But the double bonds is more stable,so it needs more energy to break it apart.
Naming Alkene To name an alkene by the IUUPAC system, find the longest chain in the molecule that contains the double bond. This chain is the parent alkene It uses suffix –ene. The chain is numbered so that the carbon atoms of the double bond have the lowest possible number Substituents on the chain are named and numbered in the same way they are for the alkanes.
Draw,name all the alkenes with the molecular formula C4H8
Identify and name the alkanes ; alkenes ;alkynes Tell which is saturated and unsaturated C 4 H 8 C 5 H 8 C 3 H 8 C 3 H 6 C 6 H 10 C 4 H 10 Alkene Butene Alkyne Pentyne Alkane Propane Alkene Propene Alkyne Hexyne Alkane Butane C 4 H 8 C 5 H 8 C 3 H 8 C 3 H 6 C 6 H 10 C 4 H 10 Alkanes are saturated compounds. Because the only bonds in it are single covalent bonds.
Isomers- - Compounds that have the same molecular formula but different molecular structures Structural isomers Stereoisomers Geometric Isomers Optical Isomers Isomers Structural Isomers Stereoisomers Geometric Isomers Optical Isomers
Structural Isomers: same molecular formula, different order. differ in physical properties. different chemical relativities.
Stereoisomers Molecules in which the atoms are joined in the same order, but the positions of the atoms in space are different. Two types : Geometric Isomers and optical Isomers G eometric Isomers have atoms joined in the same order, but differ in the orientation of groups around a double bond. O ptical Isomers are that pairs of molecules that differ only in the way that four different groups are arranged around a central carbon atom.
Geometric Isomers same order, differ in the orientation of groups around a double bond. Trans Configuration The methyl groups are on opposite sides of the double bond Cis Configuration The methyl groups are on the same side of the double bond
Asymmetric carbon is a carbon with four different atoms or groups attached Optical Isomers are that pairs of molecules that differ only in the way that four different groups are arranged around a central carbon atom.
Draw a structure formula or carbon skeleton for each of the following alkenes.If cis and trans forms are present,include both forms. a.2-pentene b.2-methy-2-pentene c.3-ethyl-2-pentene