In questions 6 and 7, we are comparing two different molecules that have the same molecular formula but different structures. Specifically, we are comparing cis-2-butene and trans-2-butene.
The difference between these two molecules lies in the geometry around the carbon-carbon double bond. In cis-2-butene, the two methyl groups (CH3) are on the same side of the double bond, while in trans-2-butene, the two methyl groups are on opposite sides of the double bond.
This difference in geometry leads to different physical and chemical properties of the two molecules, including differences in boiling point, melting point, reactivity, and stereochemistry. For example, cis-2-butene has a higher boiling point than trans-2-butene due to its greater polarity caused by the proximity of the two methyl groups on the same side. Additionally, the two isomers may react differently in certain chemical reactions due to differences in steric hindrance and orientation of functional groups relative to the double bond.
Therefore, the differences in the geometries of the carbon atoms in cis-2-butene and trans-2-butene are what provide a difference in the properties and reactivity of these molecules.