The concept of being dissolved, in the chemistry sense, means that the salt has completely broken apart at the atomic level. That is, the individual atoms from the salt are totally surrounded by water. Now take a look at the structure of the aqueous solution.
Much of the water is randomly oriented. Note, however, the structure of the water around the dissolved salt. Around the Cl, the water is oriented with the hydrogen gray part in. And around the Na the water is oriented with the oxygen red part in. I will explain why this happens in a moment. A solid has a totally organized structure with the atoms packed in a regular grid like cars stuck in a severe, big city traffic jam.
A liquid has touching atoms, yet they are randomly oriented. And a gas has randomly oriented atoms, which are not touching. So what is an aqueous solution doing? A solution mostly has touching, randomly oriented water molecules, much like a liquid.
Yet a solution also has those shells of hydration, which have a highly organized structure, much like a solid. So, a solution has less structure than a solid yet more structure than a liquid.
When you dissolve a solid into liquid water, the structure is neither solid nor liquid, and we call it an aqueous solution. The reason why water forms shells of hydration is because water is polar. This means water is like a little magnet. The hydrogen sides gray are somewhat positively charged, and the oxygen sides red are somewhat negatively charged. So water is like a little magnet, and it grabs onto other chemicals through plus-minus attractions.
This is a deeper level of understanding what dissolved means. The most abundant liquid on Earth is water, as long as it's at room temperature. Mary Lougee has been writing about chemistry, biology, algebra, geometry, trigonometry and calculus for more than 12 years. She gained the knowledge in these fields by taking accelerated classes throughout college while gaining her degree.
To be considered a liquid, all of the following properties have to be met:. They have to be almost incompressible. Their value only decreases slightly under pressure.
Liquid densities are affected by pressure but change very slightly when pressure is added. Liquids always take the shape of any type of container they are in. All the particles in a liquid have greater freedom to move about than in a solid state. Examples include many organic molecules, including fats and oils. When electrolytes—such as NaCl and KCl—dissolve in water, the ions allow the solution to conduct electricity.
Nonelectrolytes like sugar also dissolve in water, but the molecule remains intact and the solution is not conductive. Cola, saltwater, rain, acid solutions, base solutions, and salt solutions are examples of aqueous solutions. Examples of solutions that are not aqueous solutions include any liquid that does not contain water.
Vegetable oil, toluene, acetone, carbon tetrachloride, and solutions made using these solvents are not aqueous solutions. Similarly, if a mixture contains water but no solute dissolves in the water as a solvent, an aqueous solution is not formed. For example, mixing sand and water does not produce an aqueous solution. Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. Create a personalised content profile.
The hydration shell around a molecule of sucrose is arranged so that its partially negative oxygen atoms are near the partially positive hydrogen atoms in the solvent, and vice versa. Not all compounds dissolve well in water. This is because the attractions between the ions in the crystal lattice are stronger than the attraction that the water molecules have for the ions. As a result, the crystal remains intact. Nonpolar compounds also do not dissolve in water.
The attractive forces that operate between the particles in a nonpolar compound are weak dispersion forces. In order for a nonpolar molecule to dissolve in water, it would need to break up some of the hydrogen bonds between adjacent water molecules. In the case of an ionic substance, these favorable interactions are replaced by other attractive interactions between the ions and the partial charges on water. However, interactions between nonpolar molecules and water are less favorable than the interactions that water makes with itself.
When a nonpolar liquid such as oil is mixed with water, two separate layers form, because the liquids will not dissolve into each other see figure below. When a polar liquid like ethanol is mixed with water, they completely blend and dissolve into one another. Liquids that dissolve in one another in all proportions are said to be miscible. Liquids that do not dissolve in one another are called immiscible.
The general rule for deciding if one substance is capable of dissolving another is "like dissolves like", where the property being compared is the overall polarity of the substance. For example, a nonpolar solid such as iodine will dissolve in nonpolar lighter fluid, but it will not dissolve in polar water. An electrolyte is a compound that conducts an electric current when it is dissolved in water or melted.
In order to conduct a current, a substance must contain mobile ions that can move from one electrode to the other. All ionic compounds are electrolytes. When ionic compounds dissolve, they break apart into ions, which are then able to conduct a current. A nonelectrolyte is a compound that does not conduct an electric current in either aqueous solution or in the molten state.
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