Answer the following question given this paragraph: 

Thermal Expansion The intermolecular forces in liquids are strong enough to keep them from expanding significantly when heated (typically only a few percent over a 100°C temperature range). Thus the volumes of liquids are somewhat fixed. Notice from Table 11.1 "The Density of Water at Various Temperatures" that the density of water, for example, changes by only about 3% over a 90-degree temperature range. Table 11.1 The Density of Water at Various Temperatures.


Q: What forces in liquids are strong enough to keep them from expanding significantly when heated?

 Choices:

- particles forces

- outermolecular forces

- gravitational forces

- intermolecular forces

A:
intermolecular forces
