Science Buddies: "Ask an Expert"

my experiment is on storing energy with the process of splitting water to Oxygen and Hydrogen particle. where can i get nickel metal strips and a magnetic stir plate and bar without online shopping. also do i need phosphate buffer solution ph7 for my project or can i just use plain water?

Hi,

Welcome to Science Buddies! I assume that you are doing this really great, but challenging project:

https://www.sciencebuddies.org/science- ... #materials

I noticed that the nickel strips offered on the United Nuclear website and made of pure nickel are sold out.

There are not many products made of pure nickel because it is usually used as an alloy with other metals. But, here are some ideas for obtaining nickel for our project.

The Wikipedia website lists some products made of nickel. You might want to check with a local metal recycler to see if they have any of these items available that you could use to recover the nickel. I don’t know what the purity of nickel used in electric guitar strings is, for example, so you need to verify that anything you get is high purity nickel:

http://en.wikipedia.org/wiki/Nickel

You can do a Google search for “nickel electroplating your city.” This will bring up a list of local companies that do electroplating. You might want to contact one of these companies and ask if you can obtain a small quantity of nickel strips from their supply.

If you know anyone who has a supply of rechargeable batteries you might investigate whether or not you can recover the nickel from these to use for your project. You would need to check out any necessary safety precautions before you disassemble any batteries, but might be a good source of this metal.

I noticed also that the phosphate buffer is sold out on the Amazon website. Here are some ideas for substituting this item:

For the phosphate buffer, you should be able to use pH 7 phosphate buffer from a local aquarium store. You want a buffer that is pH 7 that does not contain any salt (sodium chloride) for this experiment. Here is an example of a product that should be suitable:

http://www.petguys.com/microbe-lift-buf ... gn=PetGuys

You can also check with your local pharmacy. Sterile saline, which is available in pharmacies, is phosphate buffer with sodium chloride added. Perhaps the pharmacist could supply you with just the phosphate buffer without the extra sodium chloride.

Or, please check with your teacher and find out if there are any sodium or potassium phosphate buffer salts available at school for you to use. Let me know the exact formula for these chemicals, and I will give you a recipe to make your own pH 7 buffer.

It might also be possible to make phosphate buffer from trisodium phosphate (TSP) and phosphoric acid (Lime Away) from the local hardware store, but you would need to check on the purity of these products to make sure they don’t contain large quantities of extra ions. This would be my last choice to try if the first three suggestions don’t work.

Please let us know what you use for your science project. I am very interesting in knowing what you can find to use. And do let us know if you have any other questions about doing this project.


Donna Hardy

Hi,

I realized I had not answered your question about the magnetic stir plate. Looking over the directions for this experiment, I see that the plating step with the cobalt nitrate requires continuous stirring. It would be easiest to do this with a magnetic stirrer, but it might also be possible to use hand stirring. If you try this, I recommend having a back up assistant or two to help with the stirring as this would allow you to observe the results.

Can you think of a way to make stirring the solution easier? Is there a magnetic stirrer available at your school?

Also, you do need to use phosphate buffer to ensure conductivity of the solution. Using water would increase the resistance of the solution and interfere with the chemical reaction involved in the electroplating step.

Donna Hardy

thank you for the reply. i went to my chemistry teacher about my materials. she told me she could supply me with the magnetic stir plate and buffer solution.(I'm not sure about the ingredient of the solution so i will find out more from her). i never thought of going to a recycling plant for the nickel but i will try. thanks again for the big help.

Hi,

That's good news about the stirrer. This will make the experiment a lot easier to do.

I was not certain if a nickel alloy would work for this experiment, however, Craig Bridge, one of the physical science experts on this website has suggested the using a nickel coins for this experiment. Here are his comments:

"Courtesy of the US Mint, there are plenty of nickel coins in circulation. The US nickel has a copper core that is 75% of the weight with a pure nickel outer surface that is 25% by weight. The project calls for a 5" x 0.75" thin strip of nickel but shows it stuck through a piece of styrofoam so that less than half of the material extends below the styrofoam and even less is in the solution.

BEWARE: US laws are widely drawn and there is the potential for a 6 month jail term and an unlimited fine for altering/defacing/mutilating US currency such that it can't be recirculated.

A 0.835" diameter US nickel is roughly equivalent in surface area to about 3/4 inch of the nickel strips so soldering an insulated copper wire to the top edge using tin/antimony solder (leadless solder used for copper plumbing) and then using silicone caulk to cover the solder joint and overlap the insulation to prevent tin/antimony/copper contact with the solution will work.

Alternatively, you could use an alligator clip to hold the nickel but you would have to keep the alligator clip above the level of the solution."

Nickel alloys are much more commonly available compare to pure nickel.

The buffer is a 0.1 M phosphate buffer and here is one recipe using anhydrous monobasic potassium phosphate and dibasic sodium phosphate. There are many different phosphate buffer salts available, so if you don't have these exact phosphate salts available, let me know what you do have, and I'll provide a recipe for you.

Recipe is for 500ml:
2.63 g of KH2PO4 (fw 136.09 g/mol) and 4.35 g of Na2HPO4 (fw 141.96 g/mol). Bring to 500 mL with DI water for a total phosphate concentration of 0.1 M.

Donna Hardy

hey again. i have one more question. i went to the store yesterday to get the rest of my supplies. i looked for the breadbox in Radio shack and The Source but all i found was a PC Board. i researched online and i read the only difference between the two is the PC Board requires soldering. so i was wondering if you can tell me where else of get the actual Board used for the project or if it's OK to used the PC Board instead.

thanks

Hi,

Yes, the PC board requires soldering, which would make assembling the board more complicated. Do you have solder and a soldering gun? Do you have someone who can show you how to solder?

I think it would be better to try again to get the breadboard. Radio Shack still carries part number 276-003, so you can ask your local store to order this item for you. Or, do you have a local Fry’s electronics store? They carry a breadboard that looks similar. If you go to another store, be sure to take the directions for the project with you so you can get the right size board.

Good luck!


Donna

i finally have the buffer solution. you wanted the ingredients so here it is:
Potassium Phosphate (mono basic)
Sodium Hydroxide
yellow food color -will that make a difference?
Water

i have ordered the breadboard so i will get it in about a week or so.