Physical Properties Branched alkenes have lower boiling points. Polarity--Similar to alkanes,haloalkanes. u=0 H u=0.33D C=C H CH3 C=C H H 人交 H H u=1.7D H=0D cis-2-butene,bp 4 C trans-2-butene,bp 1 Cb.p.=60c b.p.=48c difference 2.7 kcal (11 kJ) Stability of Alkenes Measured by heat of hydrogenation 30.3 kcal (127 kJ) 27.6kcal(115kJ) reaction coordinatePhysical Properties ❖Branched alkenes have lower boiling points. ❖Polarity--Similar to alkanes, haloalkanes. Cl C H C H Cl Cl C H C Cl H m = 1.7 D b.p. = 60ºc m = 0 D b.p. = 48ºc m = 0.33 D cis-2-butene, bp 4 °C C C H H3C H CH3 m = 0 trans-2-butene, bp 1 °C C C H H H3C CH3 Stability of Alkenes Measured by heat of hydrogenation