Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and...
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Transcript of Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and...
![Page 1: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/1.jpg)
Electron transfer reactions
![Page 2: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/2.jpg)
A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn.
Iron and copper sulfate
![Page 3: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/3.jpg)
The nail is coated in a layer of pink-brown copper metal.The blue Cu2+ ions have been changed into brown Cu atoms.
![Page 4: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/4.jpg)
Grey iron wool is put into blue copper sulfate solution.
![Page 5: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/5.jpg)
The wool becomes coated in brown copper. The blue colour of the solution changes to pale green.
![Page 6: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/6.jpg)
A little of the pale green solution is withdrawn and added to sodium hydroxide solution.
An olive-green precipitate forms, confirming the presence of Fe2+.Grey Fe atoms have been changed into green Fe2+ ions.
![Page 7: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/7.jpg)
Cu2+(aq) + Fe(s) → Cu(s) + Fe2+(aq)
Fe2+(aq) + 2OH-(aq) → Fe(OH)2(s)
Cu2+(aq) → Cu(s) Cu2+(aq) + 2e– → Cu(s)
Fe(s) → Fe2+(aq) Fe(s) → Fe2+(aq) + 2e–
Electrons are always added to the more positive side.
When adding half-equations, the electrons should cancel out.
![Page 8: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/8.jpg)
Grey magnesium powder is added to pale green iron(II) sulfate solution.
Magnesium powder and
iron(II) sulfate solution.
![Page 9: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/9.jpg)
The green colour fades, a large amount of black solid forms.
(Some of the magnesium powder reacts with water, producing bubbles of hydrogen gas.)
![Page 10: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/10.jpg)
The black solid is attracted to a magnet. It is iron.The Fe2+ ions have been changed into Fe atoms.
![Page 11: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/11.jpg)
Some of the liquid is withdrawn and added to sodium hydroxide solution. A white precipitate forms, which does not dissolve in excess hydroxide. This is Mg2+.The Mg atoms have become Mg2+ ions.The absence of any dark green gel shows that all the Fe2+ has reacted.
![Page 12: Electron transfer reactions. A grey iron nail is dipped into blue copper sulfate solution and immediately withdrawn. Iron and copper sulfate.](https://reader036.fdocuments.net/reader036/viewer/2022082620/5a4d1b0d7f8b9ab05998c377/html5/thumbnails/12.jpg)
Fe2+(aq) + Mg(s) → Fe(s) + Mg2+(aq)
Mg2+(aq) + 2OH-(aq) → Mg(OH)2(s)
Fe2+(aq) → Fe(s) Fe2+(aq) + 2e– → Fe(s)
Mg(s) → Mg2+(aq) Mg(s) → Mg2+(aq) + 2e–
Electrons are always added to the more positive side.