In this chapter we will learn about the interaction of ions in aqueous solution.
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An Introduction to Solutions
Water is almost single-handedly responsible for the continuity of life. Yet there is very little “pure” water in the world. For the most part, water is the main ingredient in a solution. Solutions in which water is the solvent are called aqueous solutions. There are hundreds and hundreds of different chemicals that are dissolved in water to make just as many different kinds of solutions, and those are just the ones in your body. Aqueous solutions are all around us, as well as in us. Water from the tap is a solution. The rain falling from the sky is a solution. There are many chemicals dissolved in rain. One is carbon dioxide, CO2, and it makes the rainwater slightly acidic. The oceans are not pure water. The oceans are salty because they contain sodium chloride, NaCl, as well as other salts. Even freshwater rivers, streams and lakes don’t contain pure water. Most rivers and streams contain water that in turn contain dissolved salts. Water that runs through limestone rock contains dissolved limestone, and so it contains calcium ions, Ca2+, magnesium ions, Mg2+ and carbonate ions, CO32-. Oceans, lakes, rivers and streams are all solutions.

Solutions can also contain dissolved gases. Coca-Cola is a solution that contains many different solutes including carbon dioxide gas. Carbon dioxide, CO2 gives carbonated drinks their distinctive fizz. But CO2 isn’t very soluble in water. It has a low solubility. The only way to get a lot of CO2 dissolved in water is to keep its pressure high. That is why soft-drink cans are firm before you pop the top. The cans are rigid because of the high pressure of CO2 inside the can. Once the can is opened the excess CO2 in the can is released and the CO2 that is dissolved in the “cola-water” gradually comes out of solution, and the drink goes “flat”.

Pure water is a poor conductor of electricity. But solutions that contain salts will conduct electricity very well. Ocean water and the water in swimming pools are good conductors of electricity because they contain dissolved salts that break apart into ions in solution, and the charged ions conduct electricity. The more ions that are in the solution, the better the conductor the solution will be.

A light-bulb conductivity tester won’t light up at all with pure water, but the light will glow if a substance dissolves in water and separates into charged particles called ions. But not all substances which dissolve in water will cause the light bulb to light up. Some substances, like sugar, C12H22O11, dissolve and exist as sugar molecules surrounded by water molecules. Other substances, like salt, NaCl, dissolve and separate into charged atoms – ions. Sodium ions, Na+ and chloride ions Cl-. It is the charged ions which conduct the electricity.

Part 1 - Background
Conductivity due to ions
A review of solutions, salts and ions
Demonstration: Burning magnesium in air

Part 2 - Double replacement reactions and the solubility rules
Double replacement reactions lab
The solubility rules page
Writing ionic equations (handout)
Double replacement reactions (handout 030812)
Writing ionic and net ionic equations video (YouTube)
More work with double replacement reactions (handout)

Part 3 - Applying the solubility rules
"Either-or" analysis using solubility rules
The unusual metal mercury (handout)
Qualitative analysis - Group 1: Ag, Pb, Hg(I)
Lab-based quiz - Identify the unknown solutions

Part 4 - Identifying types of reactions
Types of chemical reactions
Chemical reaction identification and balancing

Part 5 - Single replacement reactions
Single replacement reactions and the activity series ... and answers
... Demo: "Get the point?". Fe nail in CuSO4, Cu nail in FeSO4
... Video: Time lapse silver on copper
... Video: Alkali metals in water
... Demo: Al reacts with H2O in basic solution
... Demo: Al cleans tarnished silver (Ag2S)
... Lab: Al + CuCl2
Other info on single replacement reactions from the web:
.... Chemteam
.... East-Buc
.... Single replacement videos page

Part 6 - REDOX reactions
Oxidation and reduction definitions
Why redox reactions are important
Redox reactions worksheet ... answers
Introduction to half-reactions ... with answers
Half-reaction links
... Writing half-reactions ... Study through the first example
... Half-reaction tutorial
... Some practice with half-reactions ... First determine the elements oxidized and reduced
Things to know about redox ractions before the next test..... answers

Reference
A wealth of information about batteries and their chemistries (scroll to the end).
If you've ever needed to know all there is to know about lead-acid (car) batteries, here is your source.