) A hydrogel is a unique polymer network that absorbs water. To determine the equilibrium swelling content, the gel is first weighed dry. Then it is submerged in water. Water is absorbed into the gel in a time-dependent manner. After one hour, the gel is removed, the surface is blotted dry, and the sample is reweighed. Absorption of water is not a chemical reaction. Answer the above questions for the properties of water and hydrogel during the process of determining the equilibrium swelling content.