How would you expect the boiling point of methane to compare with the boiling point of water
I would expect the boiling point of methane to be much lower than the boiling point of water. Methane (CH4) is a simple hydrocarbon and consists of only one carbon atom and four hydrogen atoms. It is a nonpolar molecule with weak van der Waals forces between its molecules. Water (H2O), on the other hand, is a polar molecule with strong hydrogen bonding between its molecules. Hydrogen bonding is a much stronger intermolecular force than van der Waals forces. Consequently, water has a higher boiling point due to the stronger intermolecular attractions.
The boiling point of a substance is directly related to the strength of intermolecular forces between its particles. In the case of methane (CH4) and water (H2O), there are significant differences in their molecular structures, resulting in different intermolecular forces.
Methane is a nonpolar molecule consisting of four hydrogen atoms bonded to a central carbon atom, which gives it a tetrahedral shape. The only intermolecular force in methane is London dispersion forces, which are relatively weak compared to other intermolecular forces.
On the other hand, water is a polar molecule due to the presence of electronegative oxygen and hydrogen atoms. This polarity leads to strong hydrogen bonding between water molecules, which are relatively strong intermolecular forces.
Given that hydrogen bonding is stronger than London dispersion forces, we would expect water to have a higher boiling point than methane. Indeed, the boiling point of methane is approximately -161.6 °C (-258.9 °F), while the boiling point of water is 100 °C (212 °F) at sea level.
Therefore, the boiling point of water is significantly higher than that of methane.