which liquid, propane (C3H6) or ethanol (C2H5OH)would have the greatest surface tension?
Ethanol. Think out why. I will be happy to critique your thinking.
Notice the -OH bond on ethanol. What does that do?
To determine which liquid, propane (C3H6) or ethanol (C2H5OH), would have the greatest surface tension, we need to consider the molecular properties of each substance.
Surface tension is a measure of the cohesive forces between molecules at the surface of a liquid. It is determined by the intermolecular forces, specifically the strength of attractive forces between molecules.
In the case of propane (C3H6), the molecules are nonpolar, meaning they do not have a significant dipole moment. Propane consists of carbon and hydrogen atoms, which have similar electronegativities. Therefore, the intermolecular forces in propane are primarily van der Waals forces, which are relatively weak compared to other types of intermolecular forces.
On the other hand, ethanol (C2H5OH) is a polar molecule. The oxygen atom in ethanol has a higher electronegativity than the carbon and hydrogen atoms, creating a significant dipole moment within the molecule. This polarity leads to stronger intermolecular forces, specifically hydrogen bonding between ethanol molecules.
Hydrogen bonding is a type of intermolecular force that occurs when hydrogen atoms are covalently bonded to highly electronegative atoms, such as oxygen, nitrogen, or fluorine. The presence of hydrogen bonding in ethanol increases the strength of the cohesive forces between molecules, resulting in a higher surface tension compared to propane.
Therefore, ethanol (C2H5OH) would have the greatest surface tension between the two liquids.