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Through exhaustive experimentation, the charge of a single electron has been determined to be 1 . 602 × 10 19 size 12{1 "." "602" times "10" rSup { size 8{ - "19"} } } {} coulombs (C). (The coulomb charge unit–defined as useful for much larger charged objects–is inconvenient for expressing such a small charge, so other electrical charge units are commonly used.) One mole of electrons has a total charge calculated to be 96,485 C; this quality is defined as faraday (F):

  1 F = 96,485 C/mol e size 12{"1 F"="96,485 C/mol e" rSup { size 8{ - {}} } } {}

 Electric currents (l) are measured in amperes (A), amps for short, and defined in terms

I = Q/t

1 A = 1 C/s

 For example, a constant current of .600 A (milliamperes) over a period of 2 . 00 × 10 2 size 12{2 "." "00" times "10" rSup { size 8{2} } } {} seconds represents

Q = I × 5 = 0 . 600 A × 200s = 0 . 600 C/s × 200s = 120 C size 12{Q=I times 5=0 "." "600 A" times "200s"=0 "." "600 C/s" times "200s"="120 C"} {}

a movement of 120 coulombs. The number of moles of electrons (n) transported during the time interval is

= 1 . 24 × 10 2 mol e 1 size 12{ {}=1 "." "24" times "10" rSup { size 8{ - 2} } "mol e" rSup { size 8{ - 1} } } {}

Time intervals measured in minutes and hours must be converted to seconds in such calculations. Another useful equation in Electrochemistry is Ohm's Law, where:V = I R where V is the potential difference in volts, I is the current in amperes and R is a constant, measured in ohms, called the resistance.

Experimental procedure



CAUTION The 6 M nitric acid used in the next step will burn and stain the skin as well as damage clothing. In case of skin or clothing contact, wash the area immediately with large amounts of water.

  • Obtain a piece of copper foil (about 2 cm × 8 cm size 12{"2 cm" times "8 cm"} {} ). Holding the foil with tweezers or tongs, dip it into 6 M nitric acid several times until its surface is bright and shiny. Do not allow tweezers or tongs to touch the acid solution. Rinse the foil in de-ionized water and set it aside. This is the anode. Set the nitric acid aside to use in the electroplating exercise.
  • Obtain a piece of copper mesh (about 5 cm × 8 cm size 12{"5 cm" times "8 cm"} {} ) and remove any loose pieces of copper. Clean and rinse it as in step 1. Place the copper mesh on a watch glass in the drying oven. Be careful not to touch the cleaned surfaces. This is the cathode.
  • Add 350 mL 1.0 M KNO 3 size 12{"KNO" rSub { size 8{3} } } {} solution to a 400 mL beaker.

 CAUTION The copper sulfate used in the next step is toxic. Avoid skin contact

  • To this solution, add about 5 mL of 1 M H 2 SO 4 size 12{H rSub { size 8{2} } "SO" rSub { size 8{4} } } {} and 10 g of CuSO 4 5H 2 O size 12{"CuSO" rSub { size 8{4} } cdot "5H" rSub { size 8{2} } O} {} . Stir until the copper sulfate pentahydrate is fully dissolved.
  • Assemble the apparatus shown in Figure 1, but leave the copper mesh electrode in the oven. Add a magnetic stirring bar to the beaker. If necessary, add additional 1.0 M KNO 3 size 12{"KNO" rSub { size 8{3} } } {} to bring solution level in the beaker within 2 cm of the rim. You will either measure the electric directly with an ammeter in series with the electrolytic cell or you will measure the current indirectly by measuring the voltage across a resistor of known value (about 10 ohms).
  • Remove the copper mesh electrode from the oven, let it cool, and determine its mass to the nearest milligram.
  • Attach the copper mesh electrode to the negative terminal of your power supply using an alligator clip. Turn on the magnetic stirrer.
  • Turn on the low voltage power supply and adjust the current until about 140 mA are flowing through the cell. Record the time and current.
  • Record the time and current every five minutes for an hour.
  • After the last reading, gently remove the cathode from the solution while yet attached to the power supply. After the copper mesh has cleared the solution, remove the wire and turn off the power supply.
  • Gently dip-rinse the copper mesh electrode several times in a beaker of deionized water, and place it on a watch glass in the drying oven.
  • When dry, remove the electrode from the oven and let it cool. Reweigh the mesh electrode.
  • Remove the magnetic stirring bar from your beaker and dispose of the solution in the sink.

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
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Source:  OpenStax, Gen chem lab. OpenStax CNX. Oct 12, 2009 Download for free at http://cnx.org/content/col10452/1.51
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