REACTIONS of COMMON SUBSTANCES
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This experiment uses the computer program REACT.
The computer prints out an experiment sheet, accepts data and grades results.
Metathesis (Double decomposition) CaCl2 + Na2CO3
----> CaCO3(solid) + 2 NaCl
Calcium Chloride, CaCl2, is sold to melt ice in winter. It will melt ice at
lower temperatures than regular salt, NaCl. You will also find it as an ingredient in
canned food, where it replaces salt.
Sodium Carbonate, Na2CO3, also
known as Washing Soda or Soda Ash, is used in laundry products to improve the cleaning
power of the detergent. It does this by precipitating the calcium and magnesium ions as
carbonates. This keeps the soap from precipitating. Precipitated calcium stearate is
CaCl2 + 2 NaOOC(CH2)16CH3
---> Ca(OOC(CH2)16CH3)2 (solid) + 2 NaCl, is a common ingredient in soap. The insoluble calcium salt
forms bathtub rings.
Sodium Stearate, NaC18H35O2
Acid Base Neutralization NH3(H2O) + CH3COOH
----> NH4C2H3O2 + H2O
household ammonia is a 5% solution of NH3 in water. It is used in cleaning
where its basic properties help remove grease. Its volatility allows it to evaporate
without leaving a residue.
Acetic Acid, HC2H3O2; Vinegar is a 5% solution of this acid in water. Acids generally
have a sour taste.
Decomposition 2 NaHCO3 ----> Na2CO3 + CO2 (gas)
Sodium Bicarbonate, NaHCO3, also known as Baking Soda or
Bicarbonate of Soda, is used as a leavening in baking, in deodorizing etc. Its many common
uses reflect four things.
1. Availability at low cost; 2. Safely neutralizes acids; 3. Low toxicity; 4. Produces CO2
upon adding acid or heating.
+ 2 KI + H2O ----> I2 + NaCl + 2 KOH
Sodium Hypochlorite, NaClO, is the
active ingredient in a "chlorine bleach". These bleaches contain about 5% of the
hypochlorite. Bleaching involves the oxidizing power of sodium hypochlorite. See what happens when you add bleach to an organic dye.
Potassium Iodide, KI, is not
a common household chemical but is sometimes added to table salt ("iodized
salt"). Iodine is necessary to produce thyroxin, the thyroid gland hormone.
Disproportionation 2 H2O2
----> 2 H 2O + O2(gas)
Hydrogen Peroxide, H2O2, is used as an antiseptic on cuts and scrapes and in hair care and
bleaching. It releases Oxygen. The hydrogen peroxide you buy in a supermarket is a 3%
Addition Ce(solid) + O2
Cerium metal, Ce, while not a household word is a relatively frequently used metal.
It is the "flint" in most lighters and you will use it today to light your
burner. In a lighter, a steel file grinds off a small fresh piece of cerium metal. This
immediately oxidizes in air generating heat and light.
"Sequential" (Combination of Metathesis and Decomposition)CaCO3 (solid) + 2 HCl
----> CaCl2 + "H2CO3"
Calcium carbonate, CaCO3, occurs
naturally as the rocks limestone and marble, the mineral calcite and as clam shells. The
chalk you use to write on blackboards is partly CaCO3. It is also used
medicinally as an antacid to neutralize excess acid (HCl) in the stomach, i.e. TUMS®.
This reaction also explains why acid rain is so destructive to marble buildings or
Hydrogen Chloride, HCl, is a gas. When dissolved in
water, it ionizes and is called Hydrochloric
acid. It is sold in hardware stores as
Muriatic Acid for treatment of concrete before painting.
The "carbonic acid", "H2CO3", formed in the reaction then
decomposes to carbon dioxide a gas which bubbles out of solution. Water is also formed.
H2O + CO2 (gas)
There is a DATA