Fats are soluble in chloroform because both fats and chloroform are nonpolar molecules. Nonpolar molecules are molecules that do not have a net electrical charge. The molecules of fats and chloroform are composed of carbon and hydrogen atoms, which are both nonpolar elements. As a result, the molecules of fats and chloroform are attracted to each other and will dissolve into each other.

In contrast, polar molecules are molecules that have a net electrical charge. The molecules of water, for example, are polar molecules because they are composed of oxygen and hydrogen atoms, which have different electronegativities. As a result, the molecules of water have a positive end and a negative end. This means that the molecules of water are attracted to each other and will not dissolve into nonpolar molecules like fats and chloroform.