Word Equations
Write the chemical equation for the following reactions. You do not need to
balance.
1. When solid sodium hydrogen carbonate, NaHCO3, is heated strongly in a test
tube, carbon dioxide gas, CO2, and water vapor, H2O, are evolved from the
test tube, leaving a residue of sodium carbonate, Na2CO3.
2. Hydrogen peroxide, H2O2, is a relatively reactive chemical substance. For
example, Iron in the blood of a wound is able to trigger the decomposition of
a hydrogen peroxide solution. When it decomposes, hydrogen peroxide
produces water and oxygen gas.
3. When a small piece of sodium, is dropped into a beaker of water, a reaction
occurs that produces hydrogen gas, and dissolved sodium hydroxide.
4. Solid ammonium carbonate is used as the active ingredient in “smelling
salts”. When solid ammonium carbonate is heated it decomposes into
ammonia gas, carbon dioxide gas and water vapor.
5. When turning of magnesium metal, are added to a dilute solution of nitric
acid, hydrogen gas, is evolved as the magnesium dissolves in the acid. Upon
evaporation of the solution, solid magnesium nitrate is isolated.
6. Sulfur dioxide gas may be generated in small quantities in the laboratory by
adding aqueous sulfuric acid to solid sodium sulfite. The other products of
the reaction are sodium sulfate and water.
7. When a piece of chalk (which consists primarily of calcium carbonate) is
treated with sulfuric acid, the chalk dissolves in the acid to produce a
solution of calcium sulfate, carbon dioxide gas, and water.
8. Calcium metal is moderately reactive. If chunks of calcium are added to
water, the metal begins to bubble as hydrogen gas is formed. The water
begins to turn cloudy, as relative insoluble calcium hydroxide begins to
form.
9. When a strip of copper wire is placed in an aqueous solution of silver (I)
nitrate, solid silver precipitates out of the solution, as the copper wire
dissolves to give a solution of copper (II) nitrate.
10. If solutions of lead (II) nitrate and potassium iodide are mixed a yellow
precipitate of lead (II) iodide forms immediately and settles from the
solution. The liquid remaining is a solution of potassium nitrate.
11.Methyl alcohol (methanol) CH3OH burns cleanly in air, producing carbon
dioxide gas and water vapor.
12.If bottles of ammonia and hydrochloric acid are opened near each other, the
ammonia and hydrogen chloride fumes from the bottles react in the air,
forming solid ammonium chloride.
13.When a solution of sulfuric acid is added to solid sodium chloride and the
mixture is heated, hydrogen chloride gas is generated, leaving a solid residue
of sodium sulfate.
14.When aqueous potassium chromate is added to a solution of lead (II) nitrate,
a bright orange precipitate of lead (II) chromate forms, leaving potassium
nitrate in the solution.
15.Sand consists primarily of silicon dioxide. Pure elemental silicon for use in
the semiconductor industry can be produced by reaction of sand with
elemental carbon at high temperatures. Carbon monoxide gas is also a
product of the reaction.
16.When magnesium metal is heated to several hundred degrees in an
atmosphere of pure nitrogen gas, a green deposit of magnesium nitride
forms.
17.Although they were formerly called the inert gases, the heavier elements of
Group 18 do form relatively stable compounds. For example, at high
temperatures in the presence of a platinum catalyst, xenon gas will combine
directly with fluorine gas, to produce solid xenon tetrafluoride.
18.When a powder of bright red mercury (II) oxide is heated in a test tube,
oxygen gas is evolved, and droplets of liquid mercury condense at the cooler
top of the test tube.
19. If ordinary table sugar (sucrose, C12H22O11) is heated strongly in pure
oxygen gas, it will ignite and burn, producing carbon dioxide gas and water
vapor.
20.When a small pile of bright orange ammonium dichromate is heated
strongly, the compound decomposes with a great deal of sparking into a
large volume of green chromium (III) oxide, nitrogen gas, and water vapor.
Write the balanced chemical equation for this process.