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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

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
Do somebody tell me a best nano engineering book for beginners?
s. Reply
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?
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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