In each pair of compounds, pick the one with the higher boiling point. Explain your reasoning. c. CH₄ or CH₃CH₃

Verified step by step guidance

1. Identify the molecular structures of the compounds: CH₄ (methane) is a single carbon atom with four hydrogen atoms attached, while CH₃CH₃ (ethane) consists of two carbon atoms each bonded to three hydrogen atoms.
2. Consider the molecular weight of each compound. Generally, a higher molecular weight leads to a higher boiling point because of the increased van der Waals forces.
3. Analyze the type of intermolecular forces present in each compound. Both methane and ethane exhibit London dispersion forces, which are the only type of intermolecular forces in nonpolar molecules.
4. Compare the surface area of the molecules. Molecules with larger surface areas have stronger dispersion forces because there is more area over which the temporary dipoles can interact.
5. Conclude that the compound with the higher molecular weight, greater surface area, and consequently stronger dispersion forces will have the higher boiling point.

Key Concepts

Intermolecular Forces

Intermolecular forces are the attractive forces between molecules that influence physical properties like boiling points. The main types include hydrogen bonding, dipole-dipole interactions, and London dispersion forces. Stronger intermolecular forces typically result in higher boiling points, as more energy is required to separate the molecules.

Molecular Structure and Polarity

The molecular structure and polarity of a compound significantly affect its boiling point. Polar molecules, which have an uneven distribution of charge, tend to have higher boiling points due to stronger dipole-dipole interactions. In contrast, nonpolar molecules, like methane (CH4), exhibit weaker London dispersion forces, leading to lower boiling points.

Comparative Analysis of Compounds

When comparing compounds, it is essential to analyze their molecular weights and structures. In the case of CH4 (methane) and CH3CH3 (ethane), ethane has a larger molecular weight and more surface area, which increases its London dispersion forces. This results in ethane having a higher boiling point than methane.