Water molecules are smaller and have less mass than alcohol and oil molecules. Explain why water is more dense than alcohol and oil.

The pull of electrons is the main reason. The pull of the lone electron of hydrogen by oxygen shortens bond length; this is easily seen by looking at the electronegativity difference between oxygen and hydrogen. Although alcohol also contains a OH bond, the OH is bonded to a carbon making a longer bond. And the sharing of electrons between carbon and hydrogen causes the bond length to be longer than you would observe between oxygen and hydrogen.

***Do not copy this as an answer, but use this explanation to come up with an answer in your own words.

Water is more dense than alcohol and oil because the density of a substance depends on both the mass and the volume. Although water molecules are smaller and have less mass than alcohol and oil molecules, water is still more dense due to its unique properties.

To understand this, we need to consider the molecular structure and interactions within each substance. Water is a polar molecule, which means it has a slightly positive charge on one end (hydrogen) and a slightly negative charge on the other end (oxygen). This polarity allows water molecules to form hydrogen bonds with each other.

In the liquid state, water molecules are closely packed together due to these hydrogen bonds. This creates a three-dimensional network of interconnected water molecules, which leads to a higher density compared to substances like alcohol and oil.

Alcohol and oil, on the other hand, are nonpolar substances. This means that their molecules do not have a significant positive or negative charge. As a result, they do not form strong intermolecular forces like hydrogen bonds. Instead, alcohol and oil molecules interact primarily through weaker van der Waals forces.

The absence of strong intermolecular forces in alcohol and oil allows their molecules to move more freely and have greater space between them. Consequently, alcohol and oil have lower densities compared to water.

To summarize, water's density is higher than that of alcohol and oil because of the unique structure and intermolecular forces of water molecules. Water's polarity and the formation of hydrogen bonds result in a densely packed arrangement, whereas nonpolar substances like alcohol and oil have weaker interactions and therefore lower density.