To identify the physical properties that are different for the isomers of C4H10, we need to analyze the structural differences between the isomers in terms of their molecular formula and connectivity.
C4H10, also known as butane, has two primary isomers: n-butane and isobutane.
1. n-Butane: This is the straight-chain isomer of butane. It consists of four carbon atoms in a row, with each carbon bonded to four hydrogens. It can be represented as CH3-CH2-CH2-CH3.
2. Isobutane: This is the branched isomer of butane. It consists of a central carbon atom bonded to three methyl (CH3) groups, with the remaining carbon in the chain bonded to another hydrogen atom. It can be represented as (CH3)3C.
Now, let's discuss the differences in physical properties between these isomers:
1. Boiling Point: The boiling point of a molecule is influenced by intermolecular forces, such as van der Waals forces. Due to its linear structure, n-butane can form more extensive van der Waals interactions, resulting in stronger intermolecular forces. This leads to a higher boiling point compared to isobutane. In contrast, isobutane's branching reduces the extent of van der Waals interactions, resulting in weaker forces and a lower boiling point.
2. Melting Point: The melting point is also influenced by intermolecular forces. Similar to the boiling point, n-butane's linear structure allows for stronger van der Waals forces, leading to a higher melting point compared to isobutane.
3. Density: Density is influenced by both molecular weight and molecular packing. As n-butane has a linear structure, it has a higher molecular weight and can pack more tightly, resulting in a higher density compared to the bulky and branched isobutane.
4. Viscosity: Viscosity relates to a fluid's resistance to flow. With its linear structure, n-butane particles can align themselves in an orderly fashion, resulting in higher intermolecular attractions and higher viscosity compared to the less ordered and branched isobutane.
Overall, the physical properties (boiling point, melting point, density, and viscosity) of n-butane and isobutane differ due to the differences in molecular structure and the resulting variations in intermolecular forces and molecular packing.