Page 30 - Curriculum Visions Dynamic Book

Sodium carbonate and bicarbonate
Soda is a name used to refer to a number
of kinds of sodium compound. Sodium carbonate is also called soda ash because it was once obtained from the ashes of plants. Sodium bicarbonate is called baking soda, so named for its main use.
Sodium carbonate
Sodium carbonate is mainly used in making glass. Specifically, it is used to make the molten glass less viscous and thus easier to handle.
Sodium carbonate is also used to treat sewage and to soften water. It can also be used in the dyeing and leather-tanning industries. When combined with arsenic, sodium carbonate was an important pesticide; it also protects against bacteria.
Sodium bicarbonate in baking
Baking powder is mostly sodium bicarbonate (baking soda) together with cream of
tartar (a natural organic
acid), and small amounts of starch. It is used to make cakes rise (or leaven) as they are cooked.
Also...
Although yeast will also cause cakes to rise, its biological action is less easy to control than the straightforward chemical reactions in baking powder.
EQUATION: Producing carbon dioxide by heating baking soda
 Crystals of sodium carbonate are used as bath salts. Sodium carbonate acts as a water softener. The bath salt crystals naturally contain a large proportion of water and so they will dissolve in bath water readily.
 How baking powder works Cakes rise because of the action
of bubbles of carbon dioxide gas. Baking soda is used to produce the carbon dioxide gas.
When baking powder is added
to a wet cake mix, it changes from
a solid powder to become liquid. The soda reacts with the tartaric acid crystals to release carbon dioxide
as bubbles. These bubbles are
also released as the baking soda decomposes on being heated.
The faster the gas is released, and the bigger the bubbles of
gas produced, the more the cake will rise, and the fluffier the result. The baking powder mixture is designed to control the rate of gases before and during cooking.
Sodium bicarbonate ➪ sodium carbonate + carbon dioxide + water vapour 2NaHCO3(s) ➪ Na2CO3(s) + CO2(g) + H2O(g)
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