What is soap?
A: Soap is a salt of a fatty acid used in a variety of cleansing and
lubricating products.
In a domestic setting, soaps are surfactants usually
used for what?
A: Washing, bathing, and other types of housekeeping.
In industrial settings, soaps are used as what?
A: Thickeners, components of some lubricants, and precursors to catalysts.
When used for cleaning what does soap do?
A: Soap solubilizes particles and grime, which can then be separated from
the article being cleaned.
In hand washing, as a surfactant, when lathered with a
little water, how does soap kill microorganisms?
A: By disorganizing their membrane lipid bilayer and denaturing their
proteins.
It also emulsifies oils, enabling them to be what?
A: Carried away by running water.
How is soap made?
A: By mixing fats and oils with a base, as opposed to detergent which is
created by combining chemical compounds in a mixer.
Evidence exists for the production of soap-like
materials in ancient what?
A: Babylon around 2800 BC.
Since they are salts of fatty acids, soaps have what
general formula?
A: (RCO2−) nMn+ (Where R is an alkyl, M is a metal and n is the charge of
the cation).
When M is Na (Sodium) or K (Potassium), the soaps are
called what?
A: Toilet soaps, used for handwashing.
Many metal dications (Mg2+, Ca2+, and others) give
what?
A: Metallic soap.
When M is Li, the result is lithium soap (e.g., lithium
stearate), which is used in what?
A: High-performance greases.
Unlike detergents, when used in hard water soap does
what?
A: It does not lather well and a scum of stearate, a common ingredient in
soap, forms as an insoluble precipitate.
Soaps are key components of most what?
A: Lubricating greases and thickeners.
Greases are usually emulsions of calcium soap or
lithium soap and what?
A: Mineral oil.
In ancient times, lubricating greases were made by the
addition of what to olive oil?
A: Lime.
Sodium soaps, prepared from sodium hydroxide, are firm,
whereas potassium soaps, derived from potassium hydroxide, are what?
A: Softer or often liquid.
Historically, potassium hydroxide was extracted from
what?
A: The ashes of bracken or other plants.
For making toilet soaps, triglycerides (oils and fats)
are derived from what?
A: Coconut, olive, or palm oils, as well as tallow.
Soap made from pure olive oil is sometimes called what?
A: Castile soap or Marseille soap.
The term "Castile" is also sometimes applied to soaps
from a mixture of what?
A: Oils, but a high percentage of olive oil.
The earliest recorded evidence of the production of
soap-like materials dates back to when?
A: Around 2800 BC in ancient Babylon
A formula for making soap was written on a Sumerian
clay tablet around 2500 BC; the soap was produced by doing what?
A: Heating a mixture of oil and wood ash, the earliest recorded chemical
reaction, and used for washing woolen clothing.
The Ebers papyrus (Egypt, 1550 BC) indicates the
ancient Egyptians used soap as a what?
A: A medicine and combined
animal fats or
vegetable oils with a soda ash
substance called Trona to create their soaps.
