Chemistry for Kids
Soaps and Salts
What are salts?
In chemistry, salts are ionic compounds that are formed from the neutralization reactions of an acid and a base. Salts have certain properties:
- Salts are made up of an equal number of anions (negative ions) and cations (positive ions)
- They are hard and brittle
- Most salts dissolve in water and are solids at room temperature
- They have strong bonds and a relatively high boiling point
- Salts are electrically neutral
- In their solid state, they arrange themselves in a rigid structure called a lattice
What most people call "salt" is the chemical compound sodium chloride. It has the chemical formula NaCl. Sodium chloride dissolves in water and is what makes the ocean water salty.
Salt is necessary for animal life. It is also used to enhance the taste of our foods and to preserve foods.
Soap is a Salt
In chemistry, soap is a type of salt. This is because it is formed from the mixing of an acid and a base.
How does soap work?
Soaps and detergents help to clean clothes, skin, dirty dishes, and other items by dissolving grease. Detergents are made up of special molecules. Part of these molecules is attracted to water. The other part is attracted to grease. The part that is attracted to grease will dissolve the grease and break it up into smaller components that can then be rinsed away by water.
How is soap made?
Humans have made soap all the way back to the ancient civilizations of the Babylonians and the Egyptians. For many years soap was made from a mixture of ashes, animal fat, and water. Although we no longer make soap the same way, the chemistry for making modern soap is very similar.
Today soap is often made from a combination of fats and sodium hydroxide. As the soap is formed, the byproduct of glycerol is removed. Once the raw soap is produced, other ingredients like perfumes and colors can be added. The chemical process used to make soaps is called saponification.
Interesting Facts about Soaps and Salts
- Salts can be made by mixing an acid and a base or an acid and a metal.
- Thallium salt was once used as rat and ant poison.
- The green color of an emerald is because of small amounts of the salt chromium oxide.
- Around 250 million tons of salt was produced in 2010. Most of it is produced by the evaporation of ocean water and salt lakes.
- Glycerol, the byproduct of soap manufacturing, is used for making other chemical compounds such as plastics and explosives.
- Several different salts go into the manufacture of glass.
- Liquid soap was not invented until the late 1800s.
- Soap is a key ingredient in many lubricating greases.
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