Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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hydrochloric acid : HCl
magnesium : Mg
silver nitrate : AgNO3
copper nitrate : Cu(NO3)2 . 3H2O
ferric nitrate 9-hydrate : Fe(NO3)3 . 9H2O
Class:
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elem=N,Mg,Fe,Cu,Ag
redox
Summary:
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Finely divided magnesium powder violently reacts with wet cupric nitrate and
with wet ferric nitrate. The dry solids do not react.
Description:
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In a dry test tube, add a small amount of magnesium powder to a small amount of
ferric nitrate 9-hydrate and swirl the test tube, such that the solids mix
well: The two solids mix and nothing seems to happen for a while.
Wait a few minutes: Suddenly a very violent reaction starts. A lot of nitrogen
dioxide is formed and a lot of heat is produced. A strong hissing noise is
produced in the reaction, but no fire is observed. A very dark brown mud is
formed.
Add a small amount of concentrated hydrochloric acid: The mud dissolves and
there is a little more fizzling. The liquid becomes deep red/brown.
Add a lot of water: The liquid becomes bright yellow and remains clear.
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In a dry test tube, add a small amount of magnesium powder to a small amount of
cupric nitrate 6-hydrate and swirl the test tube, such that the solids mix
well: The two solids mix and nothing seems to happen for a while.
Wait a few minutes: Still no reaction occurs.
Add a drop of water, allow this to run along the wall of the test tube into the
mix of solids: As soon as the water reaches the mix of solids, a very violent
reaction starts. Nitrogen dioxide is produced and a white smoke/fume is
produced as well. There also is a hissing noise. A dark brown mud remains,
which also has some cyan/blue specks in it.
Add a small amount of concentrated hydrochloric acid: The mud dissolves and
there is a lot of fizzling when the acid reaches the mud. The solution becomes
clear and very dark green/brown.
Add a lot of water: The liquid becomes pale blue and turbid. Probably the dark
green/brown color was due to a mix of copper(I) and copper(II) in the
concentrated hydrochloric acid and on adding a lot of water, the copper(I)
leads to formation of a precipitate of white CuCl and the copper(II) leads to a
blue color of the solution.
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In a dry test tube, add a small amount of magnesium to a small amount of silver
nitrate and swirl the test tube such that the solids mix well: No reaction
occurs.
Wait for several minutes: Still no reaction occurs.
Add a tiny amount of water, which is allowed to run into the mix of solids: As
soon as the water reaches the mix, a bright white flash occurs and some smoke
is produced. The test tube is damaged after the flash (which must was so hot
that the glass melted at certain spots). After the reaction there are small
globules of molten and solidified metallic silver.
BEWARE: The last experiment with silver nitrate is really dangerous, the
reaction is VERY fast and intense heat is produced. Do NOT keep the test tube
in your hand and only use SMALL quantities!