Chemistry Reference
In-Depth Information
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8
9
Solutions, Acids, and Bases
Lesson 9-1: Solutions
In Lesson 1-1, you learned that solutions are homogeneous mixtures of
two or more substances physically mixed together in a uniform way. You also
learned that there are various types of solutions, including solid, liquid, and
gas solutions. In this section, we will concern ourselves with the types of solu-
tions that are in the liquid phase—that is, solids, gases, or liquids dissolved
within a liquid.
A solution is made up of two parts. The solute is the substance that gets
dissolved into the solution. The solvent is the substance that does the “dissolv-
ing.” A common example of a solution is salt water. If you mix up a glass of
salt water, the salt would be the solute, and the water would be the solvent.
Because of its ability to dissolve many substances well, water is sometimes
called the “universal” solvent. Water is a polar substance, and polar substances
dissolve other polar substances, as well as many ionic substances, well.
The ability of a substance to dissolve in another substance is called
solubility, which can be measured in a number of ways. When a substance
does not dissolve in another substance, it is called insoluble. Non-polar sub-
stances are often insoluble in polar substances. When both substances are
liquids, and the liquids fail to mix, they might be called immiscible, whereas
liquids that do mix well are called miscible.
In the chemistry laboratory activities that you carry out, you will prob-
ably be required to make several solutions, using water as a solvent. When
we talk about the solubility of a solute in water, we normally speak in
terms of the number of grams of a particular solute that will normally dis-
solve in a specific amount of water at a particular temperature. Table salt,
for example, has a solubility of about 40g of NaCl/100g of water, at 90
o
C.
