Carbon dioxide (CO2) has a relatively low boiling point compared to many other compounds due to the following factors:
Molecular Weight: Carbon dioxide has a relatively low molecular weight (approximately 44 g/mol). The boiling point of a compound is often inversely proportional to its molecular weight. Since carbon dioxide is a small molecule, it experiences weaker intermolecular forces compared to larger molecules, resulting in a lower boiling point.
Intermolecular Forces: Carbon dioxide molecules are held together primarily by weak London dispersion forces, also known as van der Waals forces. These forces are relatively weak compared to other types of intermolecular forces such as hydrogen bonding or dipole-dipole interactions. Weaker intermolecular forces lead to lower boiling points.
Molecular Shape: The molecular shape of carbon dioxide is linear. The linear shape minimizes the surface area available for intermolecular interactions, reducing the strength of intermolecular forces. As a result, it requires less energy to break these forces and transition from a liquid to a gas state, resulting in a lower boiling point.
These factors collectively contribute to the relatively low boiling point of carbon dioxide, which is approximately -78.5 degrees Celsius (-109.3 degrees Fahrenheit) at atmospheric pressure.