What does solvent mean in biology

The kidneys are responsible for filtering out substances that enter our bodies from the foods and drinks we consume. But, the kidneys have got to get rid of these substances after they accumulate them. That is where water helps out; being such a great solvent, water washing through the kidneys dissolves these substances and sends them on the way out of our bodies. This diagram shows the positive and negative parts of a water molecule.

It also depicts how a charge, such as on an ion Na or Cl, for example can interact with a water molecule. At the molecular level, salt dissolves in water due to electrical charges and due to the fact that both water and salt compounds are polar, with positive and negative charges on opposite sides in the molecule.

The bonds in salt compounds are called ionic because they both have an electrical charge—the chloride ion is negatively charged and the sodium ion is positively charged. Likewise, a water molecule is ionic in nature, but the bond is called covalent, with two hydrogen atoms both situating themselves with their positive charge on one side of the oxygen atom, which has a negative charge. When salt is mixed with water, the salt dissolves because the covalent bonds of water are stronger than the ionic bonds in the salt molecules.

The positively-charged side of the water molecules are attracted to the negatively-charged chloride ions and the negatively-charged side of the water molecules are attracted to the positively-charged sodium ions. Essentially, a tug-of-war ensues with the water molecules winning the match.

Water molecules pull the sodium and chloride ions apart, breaking the ionic bond that held them together. After the salt compounds are pulled apart, the sodium and chloride atoms are surrounded by water molecules, as this diagram shows.

Once this happens, the salt is dissolved, resulting in a homogeneous solution. Looking at water, you might think that it's the most simple thing around. Pure water is practically colorless, odorless, and tasteless.

But it's not at all simple and plain and it is vital for all life on Earth. This table identifies the solvent in familiar solutions:.

Whether or not a solute will dissolve in a solvent depends on its solubility. Solubility, in turn, depends on temperature, pressure, and the presence of other other chemicals in a mixture. For example, consider table salt sodium chloride as a solute. Table salt is much more soluble in hot water than it is in cold water water is the solvent.

It is much less soluble in certain other solvents, such as methanol or vegetable oil. Whether a solute is soluble in a solvent depends on the polarity of the compounds. A nonpolar solute like the wax tends to dissolve in a nonpolar solvent like xylene. Learn why water's chemical composition and physical attributes make it such an excellent solvent.

Water is capable of dissolving a variety of different substances, which is why it is such a good solvent. And, water is called the "universal solvent" because it dissolves more substances than any other liquid. 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.