Why does hydrophobic substances dissolve in water

This is important to every living thing on earth. It means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients. It is water's chemical composition and physical attributes that make it such an excellent solvent. Water molecules have a polar arrangement of the oxygen and hydrogen atoms—one side hydrogen has a positive electrical charge and the other side oxygen had a negative charge.

This allows the water molecule to become attracted to many other different types of molecules. Barbieri, E. Pelizzetti and P. Savarino, J. Wilhelm, R. Battino and R. Wilcock, Chem. Olofsson, A. Oshodi and E. Thermodynamics, 16 Naghibi, F. Dec and S. Gill, J. Ben-Naim, J. Wilf and H. Yaacobi, J. Wen and J. Muccitelli, J.

Scharlin and R. Battino, J. Gill, S. Nichols and I. Thermodynamics, 7 Thermodynamics, 8 Abou-Aiad, U. Becker, R. Biedenkamp, R.

Brengelmann, R. Elsebrock, H. Hinz and M. Sockhausen, Ber. Dec, G. Olofsson and I. Marshall, Biophysical Chemistry, J. Wiley, New York , p. Tucker and S. Christian, J. Tucker, E. Formation of Hydrophobic Interactions The mixing hydrophobes and water molecules is not spontaneous; however, hydrophobic interactions between hydrophobes are spontaneous.

Strength of Hydrophobic Interactions Hydrophobic interactions are relatively stronger than other weak intermolecular forces i. The strength of Hydrophobic Interactions depend on several factors including in order of strength of influence : Temperature : As temperature increases, the strength of hydrophobic interactions increases also. However, at an extreme temperature, hydrophobic interactions will denature.

Number of carbons on the hydrophobes : Molecules with the greatest number of carbons will have the strongest hydrophobic interactions. The shape of the hydrophobes : Aliphatic organic molecules have stronger interactions than aromatic compounds.

Branches on a carbon chain will reduce the hydrophobic effect of that molecule and linear carbon chain can produce the largest hydrophobic interaction. This is so because carbon branches produce steric hindrance, so it is harder for two hydrophobes to have very close interactions with each other to minimize their contact to water.

Because nonpolar molecules do not easily dissolve in water and are hydrophobic, they become squeezed together. This is how cell membranes are formed -- the water-fearing parts of the molecules all face the same direction and squeeze together to prevent water from touching them. The water cannot get through the membrane. Examples of nonpolar molecules being put in water are easily found, especially in the kitchen. Mix vegetable oil with food coloring and pour it on top of water in a clear cup.

The oil and water do not mix because water is polar and oil is nonpolar. The nonpolar molecules form a membrane between the water and oil. Notice how oil drops in the water half form drops, blocking their insides from the water.