A solution is a mixture of two or more substances. What does that mean? Well, it does not mean that sand and dirt mixed together make a solution. The two basic parts of a solution (there could be more than two parts) are the solute and the solvent. The solute is the substance that is dissolved, such as sugar. The solvent is the substance in which the solute is dissolved, like water. Aqueous solutions are solutions of substances that are dissolved in H20.
Since water conducts electricity, it's natural to touch on the topic
of electrolytes, which are solutions that can carry and electrical current.
Strong electrolytes are made of solutions where the solute is ionic, therefore
easily separable. On the other hand, solutions that contain covalent
compounds are not very good electrolytes, or weak electrolytes. Finally,
solutes that don't carry any current, such as sugar, are called nonelectrolytes.
How can you tell how concentrated a solution is? Well, you can find out in one of three ways. You can find out the solution's molarity, it's molality (no, it's not a typo), or pour the acid/base on yourself. Molarity is a way to measure the concentration by using the moles of the solute divided by the volume of the solution. Molality is a way to measure the concentration by using the moles of the solute divided by the weight of the solvent. As for pouring the acid on yourself...don't do this at home...or anywhere at all for that matter.
In order to change the concentration of a solution, an equation called the dilution equation is required. The main emphasis is that the moles of solute that you start with are the moles of solute that you end up with.
V1M1 = V2M2
The above equation is called the dilution equation. The V stands
for volume, and the M stands for molarity, or concentration.