Hydrocarbon Isomers - A Puzzle?

📌 CONCEPT: Hydrocarbon isomers are molecules with the same molecular formula but different structural arrangements of atoms, leading to distinct physical and chemical properties.

📐 RULE / FORMULA: To distinguish between isomers, we can use a laboratory method that exploits their different physical properties, such as boiling points or density.

💡 WORKED EXAMPLE: To distinguish between n-butane and isobutane, we can perform a simple distillation experiment. First, we heat a mixture of the two isomers and separate the components based on their boiling points. Since n-butane has a lower boiling point (−0.5°C) than isobutane (−11.7°C), we can collect the vapor and condense it to obtain pure n-butane, leaving isobutane behind. We can then confirm the identity of the remaining liquid by measuring its density or performing a combustion test.

⚠️ COMMON MISTAKE: Students often confuse the properties of isomers and assume that they have the same physical and chemical properties, leading to incorrect conclusions about their identity.