Final answer:
The more spherical the molecular shape, the lower the viscosity of a liquid. Long, flexible molecules tend to have higher viscosities due to increased chances of interaction and entanglement.
Step-by-step explanation:
The viscosity of a liquid is related to the molecular shape of the compounds that make up the liquid. Spherical molecules tend to create liquids with a lower viscosity, whereas long, flexible molecules, such as those found in motor oils, have a higher viscosity. This is because spherical molecules can move past each other more easily, having less opportunity to become "tangled" with one another. In contrast, longer molecules with greater surface area can interact and intertwine more easily, which increases the resistance to flow.
Furthermore, the presence of strong intermolecular forces, like hydrogen bonds, can also cause higher viscosity because these forces increase the degree of interaction between molecules, making it harder for them to slide past each other.