Cells and corrosion
Download
1 / 15

Cells and corrosion - PowerPoint PPT Presentation


  • 117 Views
  • Updated On :

Cells and corrosion. AN ACTIVITY SERIES FOR METALS. REF 353. ■ With oxygen Li, Na, K, Ca and Ba react rapidly at room temperature, while Mg, Al, Zn and Fe react slowly (but burn vigorously if heated in air or oxygen), and Sn, Pb and Cu react slowly but only if they are heated.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Cells and corrosion' - loe


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

AN ACTIVITY SERIES FOR METALS

REF 353

■ With oxygen Li, Na, K, Ca and Ba react rapidly at room temperature, while

Mg, Al, Zn and Fe react slowly (but burn vigorously if heated in air or oxygen),

and Sn, Pb and Cu react slowly but only if they are heated.

■ Li, Na, K, Ca and Ba react with water (to form hydrogen gas) while the other

metals do not.

■ With dilute acids Mg, Al, Zn, Fe react readily, Pb and Sn react if the acid is hot

and Cu, Ag, Pt and Au do not react at all.

■ In displacement reactions Zn will displace Fe, Cu and Ag from solutions of their

cations but will not displace Mg; Fe will displace Cu and Ag (but not Mg or

Zn), while Cu will only displace Ag


The activity series is a listing of metals in order of decreasing

reactivity, meaning decreasing ease of oxidation or decreasing ease of giving

up electrons.

K Na Li Ba Ca Mg Al Zn Fe Sn Pb (H) Cu Ag Pt Au

This series can be used to decide:

■ whether a metal will react with dilute acid (yes, if it is to the left of hydrogen)

■ whether a metal will react with water (only if it is on the extreme left)

■ whether metal X will reduce the cation of metal Y (yes, if X is to the left of Y)

■ whether metal P is a stronger reducing agent than metal Q (yes, if P is to the

left of Q) and conversely

■ whether metal L is a stronger oxidising agent than metal M (yes, if L is to the

right of M).


REFER TO THIS LIST

select three metals which will displace:

a lead from a solution of lead nitrate

b iron from a solution of iron(II) sulfate

Write balanced equations for these reactions.

K Na Li Ba Ca Mg Al Zn Fe Sn Pb (H) Cu Ag Pt Au



A strip of copper metal is suspended in a beaker of copper sulphate solution, and a piece of zinc in a beaker of zinc nitrate solution. The two solutions are

connected by a U-tube filled with a solution of potassium nitrate held in place by plugs of cotton wool (a strip of filter paper soaked in ammonium nitrate is often used) This U-tube which makes electrical contact between the two solutions is called a salt bridge; in order to make electrical contact it must contain some conducting substance such as a solution of potassium nitrate.

CHEMICAL REACTIONS PRODUCING ELECTRICITY


Copy sulphate solution, and a piece of zinc in a beaker of zinc nitrate solution. The two solutions are

Blank electrochemical cell showing two half cells


anode sulphate solution, and a piece of zinc in a beaker of zinc nitrate solution. The two solutions are

cathode

-2e-

salt bridge

+2e-

Zn2+

Cu

Cu2+

Zn

At this point we should move these labels


-2e sulphate solution, and a piece of zinc in a beaker of zinc nitrate solution. The two solutions are-

salt bridge

Zn

Cu

+2e-

Zn2+

Cu2+

anode

cathode


So what will happen here? sulphate solution, and a piece of zinc in a beaker of zinc nitrate solution. The two solutions are

Mg

Ag

Ag+

Mg2+

Please refer to the previous example. What electrical processes happen here. HINT Mg is the anode!


So what will happen here? sulphate solution, and a piece of zinc in a beaker of zinc nitrate solution. The two solutions are

Mg

Ag

Ag+

Mg2+

some web links follow........


http://tutors4you.com/electrochemicalcell.jpg sulphate solution, and a piece of zinc in a beaker of zinc nitrate solution. The two solutions are

http://tutors4you.com/electrochemicalcells.htm


http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/imgche/cellelece.gifhttp://hyperphysics.phy-astr.gsu.edu/hbase/chemical/imgche/cellelece.gif


http://z.about.com/d/chemistry/1/0/c/5/battery.gifhttp://hyperphysics.phy-astr.gsu.edu/hbase/chemical/imgche/cellelece.gif

http://chemistry.about.com/library/weekly/aa082003a.htm


ad