Employees in the News. Emergency Management. Survey Manual. We need to take the statement "Water is the universal solvent" with a grain of salt pun intended. Of course it cannot dissolve everything, but it does dissolve more substances than any other liquid, so the term fits pretty well.
Water's solvent properties affect all life on Earth, so water is universally important to all of us. Water is called the "universal solvent" because it is capable of dissolving more substances than any other liquid.
This is important to every living thing on earth. It means that wherever water goes, either through the air, 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 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. Molecular substances tend to be gases, liquids or low melting point solids, because the intermolecular forces of attraction are comparatively weak. You don't have to break any covalent bonds in order to melt or boil a molecular substance.
The size of the melting or boiling point will depend on the strength of the intermolecular forces. The presence of hydrogen bonding will lift the melting and boiling points. The larger the molecule the more van der Waals attractions are possible - and those will also need more energy to break. Most molecular substances are insoluble or only very sparingly soluble in water. Those which do dissolve often react with the water, or else are capable of forming hydrogen bonds with the water.
The methane , CH 4 , itself is not the problem. Molecular water, therefore is a liquid at room temperature, a fact that is profoundly significant for all living things on this planet. Everything dissolves in water. Stone, iron, pots, pans, plates, sugar, salt, and coffee beans all dissolve in water.
Things which dissolve are called solutes and the liquid in which they dissolve is called a solvent. The water molecules surround the charged solute; positive hydrogens close to negative charges and negative oxygens close to positive charges on the solute molecule.
All this interaction suspends the solute molecule in a sea of water molecules; it disperses and dissolves easily. Electrons in the bonds between identical atoms H-H are shared uniformly, so the electrons spend equal amounts of time around each atomic center. These covalent bonds are non-polar. Electrons shared between unlike atoms are not shared equally, one atom gets more of the common electrons and is thus slightly negatively charged.
Answer: Caffeine and acetaminophen are water soluble and rapidly excreted, whereas vitamin D is fat soluble and slowly excreted. Solutions are not limited to gases and liquids; solid solutions also exist.
For example, amalgams A solution usually a solid solution of a metal in liquid mercury. Because most metals are soluble in mercury, amalgams are used in gold mining, dentistry, and many other applications. A major difficulty when mining gold is separating very small particles of pure gold from tons of crushed rock. One way to accomplish this is to agitate a suspension of the crushed rock with liquid mercury, which dissolves the gold as well as any metallic silver that might be present.
The very dense liquid gold—mercury amalgam is then isolated and the mercury distilled away. An alloy is a solid or liquid solution that consists of one or more elements in a metallic matrix. A solid alloy has a single homogeneous phase in which the crystal structure of the solvent remains unchanged by the presence of the solute.
Thus the microstructure of the alloy is uniform throughout the sample. Examples are substitutional and interstitial alloys such as brass or solder.
For more information about alloys, see Chapter 12 "Solids" , Section In contrast, a partial alloy solution has two or more phases that can be homogeneous in the distribution of the components, but the microstructures of the two phases are not the same.
As a liquid solution of lead and tin is cooled, for example, different crystalline phases form at different cooling temperatures. As you learned in Chapter 12 "Solids" , alloys usually have properties that differ from those of the component elements. Network solids such as diamond, graphite, and SiO 2 are insoluble in all solvents with which they do not react chemically. The covalent bonds that hold the network or lattice together are simply too strong to be broken under normal conditions.
They are certainly much stronger than any conceivable combination of intermolecular interactions that might occur in solution.
Most metals are insoluble in virtually all solvents for the same reason: the delocalized metallic bonding is much stronger than any favorable metal atom—solvent interactions. Many metals react with solutions such as aqueous acids or bases to produce a solution.
However, as we saw in Section Solids with very strong intermolecular bonding tend to be insoluble. Table 4. Ionic substances are generally most soluble in polar solvents; the higher the lattice energy, the more polar the solvent must be to overcome the lattice energy and dissolve the substance. Because of its high polarity, water is the most common solvent for ionic compounds. Many ionic compounds are soluble in other polar solvents, however, such as liquid ammonia, liquid hydrogen fluoride, and methanol.
Because all these solvents consist of molecules that have relatively large dipole moments, they can interact favorably with the dissolved ions. Because the dipole moment of acetone 2. This apparent contradiction arises from the fact that the dipole moment is a property of a single molecule in the gas phase. By definition, the dielectric constant of a vacuum is 1.
In essence, a solvent with a high dielectric constant causes the charged particles to behave as if they have been moved farther apart. This behavior is in contrast to that of molecular substances, for which polarity is the dominant factor governing solubility. Figure It is also possible to dissolve ionic compounds in organic solvents using crown ethers Cyclic polyether with four or more oxygen atoms separated by two or three carbon atoms.
All crown ethers have a central cavity that can accommodate a metal ion coordinated to the ring of oxygen atoms. Crown ethers are named using both the total number of atoms in the ring and the number of oxygen atoms. Thus crown-6 is an membered ring with six oxygen atoms part a in Figure The cation is stabilized by interacting with lone pairs of electrons on the surrounding oxygen atoms.
Thus crown ethers solvate cations inside a hydrophilic cavity, whereas the outer shell, consisting of C—H bonds, is hydrophobic. The availability of crown ethers with cavities of different sizes allows specific cations to be solvated with a high degree of selectivity.
Note how the cation is nestled within the central cavity of the molecule and interacts with lone pairs of electrons on the oxygen atoms. Cryptands solvate cations via lone pairs of electrons on both oxygen and nitrogen atoms. Cryptands Consisting of three — OCH 2 CH 2 O— n chains connected by two nitrogen atoms, cryptands have a central cavity that can encapsulate a metal ion coordinated to the oxygen and nitrogen atoms.
The number in the name of the cryptand is the number of oxygen atoms in each strand of the molecule. Like crown ethers, cryptands can be used to prepare solutions of ionic compounds in solvents that are otherwise too nonpolar to dissolve them. The solubility of a substance is the maximum amount of a solute that can dissolve in a given quantity of solvent; it depends on the chemical nature of both the solute and the solvent and on the temperature and pressure.
When a solution contains the maximum amount of solute that can dissolve under a given set of conditions, it is a saturated solution. Otherwise, it is unsaturated. Supersaturated solutions , which contain more dissolved solute than allowed under particular conditions, are not stable; the addition of a seed crystal , a small particle of solute, will usually cause the excess solute to crystallize.
A system in which crystallization and dissolution occur at the same rate is in dynamic equilibrium. The solubility of a substance in a liquid is determined by intermolecular interactions, which also determine whether two liquids are miscible.
Solutes can be classified as hydrophilic water loving or hydrophobic water fearing. Vitamins with hydrophilic structures are water soluble, whereas those with hydrophobic structures are fat soluble.
Many metals dissolve in liquid mercury to form amalgams. Covalent network solids and most metals are insoluble in nearly all solvents.
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