Chem Car Help

[ChemCar]

Hey everyone! Hate to admit this but was google-ing for some answers about electroplating Copper in CuSO4 and came upon this site. My problem consists of building a stopping mechanism for a lithium powered shoe-box car. My groups plan was to break the circuit by dissolving a copper wire in CuSO4 solution by electroplating it into solution. If anyone can help me out here, I really need to know if you guys would know of any tables out there relating copper wire thickness vs time to break circuit under constant voltage.

 

Thanks a bunch!

ChemCar

[Turtle]

Googlin' for answers is never something to apologize for. :) ;)

 

Is the copper wire you plan to dissolve part of the drive circuit, or is it isolated by a relay?

 

What is the time interval that you need between start & stop?

 

The electrolyte does not need copper in it. Salt water works OK and is harmless.

 

What voltage do you have to work with?

 

That's all I got. :D :shrug:

[alexander]

i can think of better ways of disengaging the drive then dissolving something in acid, i mean yea its cool and all, BUT, better ways of doing that... a small circuit will cut the power exactly at a determined time for example...

[Turtle]

i can think of better ways of disengaging the drive then dissolving something in acid, i mean yea its cool and all, BUT, better ways of doing that... a small circuit will cut the power exactly at a determined time for example...

 

ChemCar does not mention acid. CuSO4 is copper sulphate, and as I read it, he describes using it dissoved in water as an electrolyte and to dissolve the negative copper lead through electrolysis.

 

I see some problems too, but "better ways" in the class may mean "different ways". ;) I'm anxious to hear back from ChemCar on this interesting idea. :)

[alexander]

and that is exactly why i'm NOT a chemistry person... it would be yet another field to investigate, and i dont have time for all my current hobbies...

[Turtle]

and that is exactly why i'm NOT a chemistry person... it would be yet another field to investigate, and i dont have time for all my current hobbies...

 

I admit I had to look up CuSO4. :hihi: I'm not much on chem knowledge either, but I have experimented a lot with electrolysis.

 

What I'm thinking on ChemCar's suggestion is that the wire getting dissolved in the electrolyte is supplying power to the motor and to get that to work it has to be the negative side and there also has to be a positive terminal in the electrolyte to make the dissolving circuit complete. So if the power to the electrolytic cell is the same as to the motor then the cell will short cicuit the motor if only at least acting as a resistor & making the motor run slower???

 

Anyways, that's all I got....again. ;) :)

[ChemCar]

CuSo4 from what i understand will act as the electrolyte for a electrolytic reaction for the Cu. That was my plan in the beginning anyways, but looking more into it i might have to have an anode with another metal in which the dissolved Cu has a place to go after being dissolved. Apparently it doesn't like being in solution. We are planning on testing this around monday, hopefully. We might have to go in another direction and just have the Cu dissolve in a relatively high concentration of acid. A bit easier on the design, but might propose a safety concern. LOL.

 

Some background info on the contest:

We have to design a car that:

is ran on a chemical process

has to stop by means of a chemical process to a desired distance, (judges pick the distance at the event)

no circuit timers/remote controls/nor-human interaction is permitted

has to be the size of a shoe-box

we only have $250 to spend

 

Our plan:

My group and I decided to use a lithium battery to power a motor. And with in the circuit we will have a wire (to a certain thickness) of Cu that will be either sitting in CuSo4 solution or a strong acid in which will be getting dissolved at a constant rate. From this we can calculate how long our circuit will last thus how far our car will go. In theory anyways...lol

[Turtle]

CuSo4 from what i understand will act as the electrolyte for a electrolytic reaction for the Cu. That was my plan in the beginning anyways, but looking more into it i might have to have an anode with another metal in which the dissolved Cu has a place to go after being dissolved. Apparently it doesn't like being in solution.

 

As I said, salt water will suffice for the electrolyte. The dissolved copper leaving the negative terminal, is deposited/plated onto the positive terminal in an ideal situation, although in reality some copper may form films/precipitates in the electrolyte.

 

We are planning on testing this around monday, hopefully. We might have to go in another direction and just have the Cu dissolve in a relatively high concentration of acid. A bit easier on the design, but might propose a safety concern. LOL.

I think since it is chemistry class, a small amount of acid sufficient to dissolve a fine copper wire is not beyond safety.

 

I think there is more to the electrolysis than you imagine. This thread may help some, or at least it can't hurt much. :naughty: >> Hydrogen Product By Photovoltaic Electolytic Cell

 

Some background info on the contest:

We have to design a car that:

is ran on a chemical process

has to stop by means of a chemical process to a desired distance, (judges pick the distance at the event)

no circuit timers/remote controls/nor-human interaction is permitted

has to be the size of a shoe-box

we only have $250 to spend

 

Our plan:

My group and I decided to use a lithium battery to power a motor. And with in the circuit we will have a wire (to a certain thickness) of Cu that will be either sitting in CuSo4 solution or a strong acid in which will be getting dissolved at a constant rate. From this we can calculate how long our circuit will last thus how far our car will go. In theory anyways...lol

 

Thanks for the nice description. By all means come back & let us know how it goes. :naughty:

[alexander]

Some background info on the contest:

We have to design a car that:

is ran on a chemical process

has to stop by means of a chemical process to a desired distance, (judges pick the distance at the event)

no circuit timers/remote controls/nor-human interaction is permitted

has to be the size of a shoe-box

we only have $250 to spend

 

now that just spells rocket car

 

i would use a reaction with a large release of gases to lift the thing using air foil

propell the car with 1 or 2 small engines (rocket)

and stop it with a reaction to produce sticky, gluey foam, or just blow up the damn thing at the end of the run :naughty:

 

the most wasteful car... but the most fun to watch in the run :naughty:

[modest]

Hey everyone! Hate to admit this but was google-ing for some answers about electroplating Copper in CuSO4 and came upon this site. My problem consists of building a stopping mechanism for a lithium powered shoe-box car. My groups plan was to break the circuit by dissolving a copper wire in CuSO4 solution by electroplating it into solution. If anyone can help me out here, I really need to know if you guys would know of any tables out there relating copper wire thickness vs time to break circuit under constant voltage.

 

Howdy ChemCar, welcome to Hypo :)

 

To calculate this you would use Faraday's Law

[math]m=\frac{I \times t \times M}{F \times z}[/math]

where

• m is the mass of the electrode that will be dissolved
  
• I is current in coulombs per second
  
• t is time in seconds
  
• M is the molar mass of the electrode
  
• F is Faraday’s constant (96485 C/mol)
  
• z is the valence number of ions of the substance (electrons transferred per ion)
  

A good example is worked out on this page: Faraday's Law

 

CuSo4 from what i understand will act as the electrolyte for a electrolytic reaction for the Cu. That was my plan in the beginning anyways, but looking more into it i might have to have an anode with another metal in which the dissolved Cu has a place to go after being dissolved.

You have to have a cathode to complete the cell and accomplish electrolysis. The cathode can be copper just like the anode. The two reactions happening would be:

Cathode: [ce]Cu^{2+}_{(aq)} + 2e^- -> Cu_{(s)}[/ce]

Anode: [ce]Cu_{(s)} -> Cu^{2+}_{(aq)} + 2e^-[/ce]

I would also second Turtle’s motion that it sounds like you might be underestimating what all is necessary to implement what you’re looking for.

We are planning on testing this around monday, hopefully. We might have to go in another direction and just have the Cu dissolve in a relatively high concentration of acid. A bit easier on the design, but might propose a safety concern. LOL.

Copper is dissolved by nitric acid, but you should *not* do this in your car—the reaction liberates nitrogen dioxide which is very toxic. Sulfuric acid would likewise liberate sulfur dioxide, so use a hood if you're mixing acids and copper.

 

Also, dissolving a wire in an electrolyte or acid would not necessarily break the circuit because electrolytes and acids are usually both highly conductive.

 

You might construct a thermostat (or buy a mercury one), then use some ammonium nitrate to lower the temperature of some water. The amount of time it takes the ammonium nitrate to cool the water to a preset point would be the duration the car runs.

 

Good luck.

 

~modest