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displacement

This version was saved 13 years, 4 months ago View current version     Page history
Saved by alfredo
on February 21, 2008 at 1:31:22 pm
 

Displacement reactions of copper oxide with active elements: Hydrogen, Magnesium, Carbon.

reazioni di spostamento dell'ossido di rame con elementi attivi: Idrogeno, Magnesio, Carbonio. 

 

Reaction 1

Ossido rameico + idrogeno --> Rame + Ossido di idrogeno (acqua)

Cupric oxide + Hydrogen --> Copper + Hydrogen oxide (water)

The two former preparatory steps weren't shown by the video: 1. Heating of copper in air to oxidize its suface. Copper was "roasted" in the bubble of a pipette until it became completely black. 2. An hydrogen stream was made by adding 100 mL of 6M sulphuric acid into a lot of zinc beads in a separated Erlenmeyer flask. Hydrogen gas was collected in a pipeline and forced to pass through the bubble pipette. To have a demonstration of constant flow, the escaping hydrogen gas was ignited from the opposite orifice of the pipette. The following video starts from here.

 

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Reaction 2

Ossido rameico + magnesio --> Rame + Ossido di magnesio

Cupric oxide + Magnesium --> Copper + Magnesium oxide

 

In this experiment we mixed a powder of black cupric oxide and gray magnesium metal filings in a test tube. Our teacher warned us to dress security glasses and to keep away from the flame. He placed the test tube on the bunsen flame with prolonged forceps to protect himself from possible explosions. A ceramics plate was fastened perpendicularly to the flam to stop possible ejections of melted matter towards the ceiling. Some paper was placed under the bunsen to protect our lab bench surface from etching with possible melted matter. We got disappointed because nothing exploded and our teacher kept alive, but temperature in the tube went higher than 1500 °C due to the reaction heat and the glass of the test tube resulted partially melted. FInally the hot tube was submerged in a beacker with cold water to crash it, permitting us to recovery pellets of metal copper from the black matter.

 

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Two better views or experiment 2

2.1: the solid mixture of Magnesium and copper oxide get glowing

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2.2 Recovery of copper from the cooled mixture

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Reaction 3

Ossido rameico + carbone --> Rame + Ossido di carbonio

Cupric oxide + Carbon --> Copper + Carbon oxide

Our teacher begins heating the black miture holding the test tube over the flame, without extension of the clamps because, as he tells: "there is no need to prolonge clamps, because this reaction is very safe". But the things went different. Our teacher kept alive again, but after the experiment we all realized that safety cannot be based on past experience only.

 

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Complete experiment from a different perspective.

 

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